Substrate processing method

ABSTRACT

A substrate processing method includes a first process (step S 12  to step S 16 ) of forming a first resist pattern by exposing a substrate having thereon a first resist film to lights, developing the exposed substrate and cleaning the developed substrate; and a second process (step S 17  to step S 20 ) of forming a second resist pattern by forming a second resist film on the substrate having thereon the first resist pattern, exposing the substrate having thereon the second resist film to lights, and developing the exposed substrate. A first processing condition is determined based on first data showing a relationship between a first processing condition under which a cleaning process is performed on the substrate in the first process (step S 16 ) and a line width of the second resist pattern, and the first process (step S 16 ) is performed on the substrate under the determined first processing condition.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Japanese Patent Application Nos.2010-029339 and 2010-266897 filed on Feb. 12, 2010 and Nov. 30, 2010,respectively, the entire disclosures of which are incorporated herein byreference.

FIELD OF THE INVENTION

The present disclosure relates to a substrate processing method forprocessing a substrate.

BACKGROUND OF THE INVENTION

In manufacturing a semiconductor device, there has been usedphotolithography as a patterning technique for forming a circuit patternon a semiconductor wafer (hereinafter, simply referred to as “wafer”) asa processing target substrate. In order to form the circuit pattern byusing photolithography, a resist film is formed on a wafer by coatingthe wafer with a resist solution, the resist film is exposed to lightsirradiated onto the resist film so as to correspond to the circuitpattern, and then the exposed resist film is developed.

Recently, as a semiconductor device is operated at high speed and tendsto be highly integrated, a circuit pattern formed on a wafer is requiredto be miniaturized by a patterning technique using photolithography. Forthis reason, conventionally, light of a shorter wavelength has been usedfor an exposure process, but it is not sufficient for anultra-miniaturized semiconductor device after 45 nm node.

Here, as a patterning technique used for the ultra-miniaturizedsemiconductor device after 45 nm node, it has been proposed that when apattern is formed on a single layer, patterning using photolithographyis performed a plurality of times (see, for example, Patent Document 1).For example, double patterning is a technique of performing patterningprocess two times.

One of double patterning techniques is a lithography lithography etching(LLE) process. In the LLE process, a first resist pattern is formed byperforming a first patterning process and a second resist pattern isformed by performing a second pattering process, and an etching processis performed by using the first and second resist patterns as masks.

Patent Document 1: Japanese Patent Laid-open Publication No. H07-147219

However, if resist patterns are formed by performing double patterningsuch as the above-described LLE process, there is a following problem.

In the first patterning process, a first resist film is formed on awafer and then exposed and developed, so that the first resist patternis formed. Thereafter, in the second patterning process, a second resistfilm is formed on the wafer, on which the first resist film is formed,and then exposed and developed, so that the second resist pattern isformed.

Here, after the development process of the first patterning process, acleaning process is performed. However, if the cleaning process is notperformed sufficiently, there may occur a development failure in thedevelopment process of the second patterning process, which may resultin non-uniformity in line widths of the second resist pattern.Particularly, the line widths of the second resist pattern are notuniform between a central area of the wafer and a periphery area of thewafer.

By way of example, in order to sufficiently perform the cleaningprocess, it is desirable that a sufficiently long time be spent on thecleaning process. However, the sufficiently long time for the cleaningprocess may increase a time for processing a single sheet of a wafer,i.e., a so-called “tact time”, and, thus, the number of processed wafersper unit time may decrease and productivity may be lowered.

BRIEF SUMMARY OF THE INVENTION

In view of the foregoing, the present disclosure provides a substrateprocessing method capable of reducing non-uniformity in line widths of asecond resist pattern on a wafer surface without lowering productivitywhen resist patterns are formed by performing double patterning such asa LLE process.

In order to solve the above-described problem, the present disclosureprovides a method as explained below.

In accordance with an embodiment of the present disclosure, there isprovided a substrate processing method for processing a substrate. Thesubstrate processing method includes a first process of forming a firstresist pattern by exposing the substrate having thereon a first resistfilm to lights, developing the exposed substrate and cleaning thedeveloped substrate; and a second process of forming a second resistpattern by forming a second on the substrate having thereon the firstresist pattern, exposing the substrate having thereon the second resistfilm to lights, and developing the exposed substrate. Here, a firstprocessing condition may be determined based on first data showing arelationship between a first processing condition under which a cleaningprocess is performed on the substrate in the first process and a linewidth of the second resist pattern. Further, the first process may beperformed on the substrate under the determined first processingcondition.

In accordance with the present disclosure, when resist patterns areformed by performing double patterning such as a LLE process, it ispossible to reduce non-uniformity in line widths of a second resistpattern on a wafer without lowering productivity.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments will be described inconjunction with the accompanying drawings. Understanding that thesedrawings depict only several embodiments in accordance with thedisclosure and are, therefore, not to be intended to limit its scope,the disclosure will be described with specificity and detail through useof the accompanying drawings, in which:

FIG. 1 is a plane view showing a schematic configuration of a substrateprocessing system in accordance with a first embodiment;

FIG. 2 is a perspective view showing a schematic configuration of thesubstrate processing system in accordance with the first embodiment;

FIG. 3 is a longitudinal cross sectional view of a developing unit;

FIG. 4 is a schematic plane view of the developing unit;

FIGS. 5A and 5B show a cleaning solution nozzle provided in thedeveloping unit;

FIG. 6 is a plane view of the cleaning solution nozzle provided in thedeveloping unit;

FIG. 7 is a side view of a gas nozzle and a nozzle driving mechanismprovided in the developing unit;

FIG. 8 is a longitudinal cross sectional view showing a schematicconfiguration of a line width measurement apparatus;

FIG. 9 is a flow chart for explaining a sequence of processes of asubstrate processing method in accordance with the first embodiment;

FIGS. 10A to 10J are cross sectional views showing a status of a waferin each process of the substrate processing method in accordance withthe first embodiment;

FIGS. 11A and 11B are plane views showing a status of the wafer in eachprocess of a cleaning process in accordance with the first embodiment;

FIG. 12 is a graph schematically showing a relationship between aprocessing time and a space width of a second resist pattern;

FIGS. 13A and 13B show distribution of space widths of a second resistpattern in a wafer surface obtained by performing substrate processingmethods in accordance with the first embodiment and a comparativeexample 1;

FIG. 14 is an example of first data showing a relationship between aprocessing time and a space width of a second resist pattern when atemperature or a flow rate of a cleaning solution is modified;

FIG. 15 is another example of first data showing a relationship betweena processing time and a space width of a second resist pattern when atemperature or a flow rate of a cleaning solution is modified;

FIG. 16 is still another example of first data showing a relationshipbetween a processing time and a space width of a second resist patternwhen a temperature or a flow rate of a cleaning solution is modified;

FIG. 17 is a flow chart for explaining a sequence of processes of asubstrate processing method in accordance with a first modificationexample of the first embodiment;

FIG. 18 is a graph schematically showing a relationship between aprocessing time and a space width of a second resist pattern;

FIG. 19 is a flow chart for explaining a sequence of processes of asubstrate processing method in accordance with a second modificationexample of the first embodiment;

FIG. 20 is a graph schematically showing a relationship between atemperature of a cleaning solution and a space width of a second resistpattern;

FIG. 21 is a graph schematically showing a relationship between a flowrate of a cleaning solution and a space width of a second resistpattern;

FIG. 22 is a graph schematically showing a relationship between pH of acleaning solution and a space width of a second resist pattern;

FIG. 23 is a flow chart for explaining a sequence of processes of asubstrate processing method in accordance with a third modificationexample of the first embodiment;

FIG. 24 is a graph schematically showing a relationship between aprocessing time, a temperature of a cleaning solution and a space widthof a second resist pattern;

FIG. 25 is a graph schematically showing a relationship between aprocessing time, a flow rate of a cleaning solution and a space width ofa second resist pattern;

FIG. 26 is a graph schematically showing a relationship between aprocessing time, pH of a cleaning solution and a space width of a secondresist pattern;

FIG. 27 is a flow chart for explaining a sequence of processes of asubstrate processing method in accordance with a fourth modificationexample of the first embodiment;

FIG. 28 is a flow chart for explaining a sequence of processes of acleaning process of a substrate processing method in accordance with asecond embodiment;

FIGS. 29A to 29E are perspective views showing a status of a wafer ineach process of the cleaning process in the second embodiment;

FIGS. 30A to 30C are perspective views showing a status of a wafer ineach process of a cleaning process in a modification example of thesecond embodiment; and

FIGS. 31A and 31B show distribution of space widths of a second resistpattern in a wafer obtained by performing substrate processing methodsin accordance with the modification example of the first embodiment anda comparative example 2.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present disclosure will be describedwith reference to the accompanying drawings.

First Embodiment

Above all, a substrate processing method and a substrate processingsystem employing the substrate processing method in accordance with afirst embodiment will be explained with reference to FIGS. 1 to 14.

Referring to FIGS. 1 and 2, a substrate processing system in accordancewith the present embodiment will be explained. In this substrateprocessing system, a coating/developing apparatus is connected with anexposure apparatus.

FIG. 1 is a plane view showing a schematic configuration of a substrateprocessing system in accordance with the present embodiment, and FIG. 2is a perspective view showing a schematic configuration of the substrateprocessing system in accordance with the present embodiment.

The substrate processing system includes a carrier mounting unit B1, aprocessing unit B2, an interface unit B3, and an exposure unit B4.

The carrier mounting unit B1 includes a carrier station 20, anopening/closing unit, and a transit mechanism A1. The carrier station 20includes a mounting unit 20 a that loads and unloads a carrier C1 inwhich, for example, sheets of wafers W are airtightly accommodated. Theopening/closing unit 21 is provided on a wall surface on the front sideof the carrier station 20. The transit mechanism A1 takes out the wafersW from the carrier C1 via the opening/closing unit 21.

Further, as depicted in FIG. 2, provided at a lower part of the carriermounting unit B1 is a main controller 10 that controls the entiresubstrate processing system. Furthermore, as depicted in FIGS. 1 and 2,provided in the carrier mounting unit B1 is a line width measurementapparatus 110 that measures a line width of a resist pattern on thewafer W. The main controller 10 and the line width measurement apparatus110 will be described in detail later.

The processing unit B2 surrounded by a housing 22 is connected with aninner side of the carrier mounting unit B1. The processing unit B2includes rack units U1, U2, and U3; liquid processing units U4 and U5;and main transfer mechanisms A2 and A3. The rack units U1, U2, and U3and the main transfer mechanisms A2 and A3 are alternately arranged insequence when viewed from the carrier mounting unit B1.

The rack units U1, U2, and U3 are heating/cooling units stacked inmultiple levels. The rack units U1, U2, and U3 includes various units,stacked in multiple levels, e.g., ten levels, for performing apre-treatment and a post-treatment of a process performed by the liquidprocessing units U4 and U5. These various units include a heating unitfor heating (baking) the wafer W and a cooling unit for cooling thewafer W.

The main transfer mechanisms A2 and A3 are installed in a spacesurrounded by partition walls 23. The main transfer mechanism A2delivers the wafer W between the rack units U1 and U2 and the liquidprocessing unit U4. The main transfer mechanism A3 delivers the wafer Wbetween the rack units U2 and U3 and the liquid processing unit U5.

Further, provided in the processing unit B2 are temperature/humiditycontrol units 24 and 25 including a temperature control device for aprocessing solution used in each unit or a duct for controllingtemperature and humidity.

As depicted in FIG. 2, the liquid processing units U4 and U5 includescoating units (COT) 27, developing units (DEV) 28, antireflection filmforming units BARC, topcoat film forming units TC staked in multiplelevels, e.g., five levels on liquid chemical accommodation units 26 foraccommodating, for example, a resist solution or a developing solution.

The interface unit B3 includes a first transfer chamber 3A and a secondtransfer chamber 3B. The first transfer chamber 3A and the secondtransfer chamber 3B are arranged back and forth between the processingunit B2 and the exposure unit B4. Provided in the first transfer chamber3A and the second transfer chamber 3B are a first substrate transferunit 31A and a second substrate transfer unit 31B, respectively.Provided in the first transfer chamber 3A are a rack unit U6, a buffercassette C0, and a substrate cleaning apparatus 4. The rack unit U6includes a heating unit PEB for performing a baking process (PEBprocess) on an exposed wafer W after an exposure process and ahigh-precision temperature control unit including a cooling plate, thatare vertically arranged.

Further, the exposure unit B4 is connected with an inner side of therack unit U3 of the processing unit B2 via the interface unit B3.

Hereinafter, the developing unit (DEV) 28 will be explained withreference to FIGS. 3 to 7. FIG. 3 is a longitudinal cross sectional viewof the developing unit. FIG. 4 is a schematic plane view of thedeveloping unit. FIGS. 5A and 5B show a cleaning solution nozzleprovided in the developing unit. To be specific, FIG. 5A is aperspective view of the cleaning solution nozzle and FIG. 5B shows aninclined lower part of the cleaning solution nozzle when viewed from thebottom thereof. FIG. 6 is a plane view of the cleaning solution nozzleprovided in the developing unit. FIG. 7 is a side view of a gas nozzleand a nozzle driving mechanism provided in the developing unit.

As depicted in FIGS. 3 and 4, the developing unit (DEV) 28 includes acase 41, a shutter 42, a cup 43, a wafer holder 44, a discharge line 45,supporting pins 46, a developing solution nozzle 5, a cleaning solutionnozzle 6, a gas nozzle 7, and a controller 100.

The case 41 serves as an exterior body of the apparatus. The shutter 42is provided at the case 41 and opens and closes a transfer port for thewafer W. The cup 43 is provided within the case 41. The wafer holder 44is provided so as to be rotatable around a vertical shaft within the cup43. The wafer holder 44 is configured to horizontally hold and rotatethe wafer. The wafer holder 44 includes a driving unit 44 a. The drivingunit 44 a is configured to rotate the wafer holder 44. The dischargeline 45 is connected with a bottom portion of the cup 43. The dischargeline 45 is exhausted by a non-illustrated exhaust mechanism and agas-liquid division unit is provided on the discharge line 45. Thesupporting pins 46 are configured as, for example, three pins forsupporting and elevating the wafer W. The supporting pins 46 include anelevating member 46 a and an elevating mechanism 46 b. The elevatingmember 46 a is configured to hold the supporting pins 46. The elevatingmechanism 46 b is configured to move the elevating member 46 a up anddown.

The developing solution nozzle 5 is configured to supply a developingsolution onto a surface of the wafer W. In the same manner as thecleaning solution nozzle 6 to be described later with reference to FIGS.5A and 5B, the developing solution nozzle 5 includes a strip-shapeddischarge opening, for example, a slit-shaped discharge opening. Anupper portion of the developing solution nozzle is connected with adeveloping solution supply line 53. Further, the developing solutionsupply line 53 is connected with a developing solution supply source 55via a group of supply devices 54 including a valve or a flow ratecontrol unit as depicted in FIG. 3.

As depicted in FIG. 4, the developing solution nozzle 5 is fixed at anarm 56 and the arm 56 is configured to move in an X direction and in avertical direction. The arm 56 is bent in an L shape and configured tostraightly move along a guide rail 57 a (in the X direction) at thebottom of the case 41 by a driving mechanism 57 in the same manner as anarm 76 to be described later with reference to FIG. 7. Further, by wayof example, the arm 56 can be moved in the vertical direction by anelevating mechanism included in the driving mechanism 57.

The cleaning solution nozzle 6 is configured to supply a cleaningsolution onto the surface of the wafer W. As depicted in FIGS. 5A and5B, the cleaning solution nozzle 6 includes a bent lower part 61 a and asquare tube-shaped main body 61, and the cleaning solution nozzle 6 isconfigured to supply a cleaning solution to the surface of the wafer Wthrough a slit-shaped discharge opening 62 formed on the underside ofthe lower part 61 a in a slanted direction. The discharge opening 62 isnot limited to a slit-shaped one and, for example, may be formed of aplurality of round holes of a small diameter arranged at the lower part61 a of the main body 61 in a longitudinal direction thereof.

An upper part of the main body 61 of the cleaning solution nozzle 6 isconnected with a cleaning solution supply line 63 as depicted in FIG.5A. Further, the cleaning solution supply line 63 is connected with acleaning solution supply source 65 that supplies a cleaning solutionsuch as pure water via a group of supply devices 64 including a valve ora flow rate control unit as depicted in FIG. 3.

As depicted in FIG. 6, the main body 61 of the cleaning solution nozzle6 is connected with an arm 66 via a support 61 b on its rear surface soas to adjust the direction of the main body 61 around the verticalshaft. As depicted in FIG. 4, in the same manner as an arm 76 to bedescribed later with reference to FIG. 7, the arm 66 is bent in an Lshape and configured to straightly move along a guide rail 57 a (in theX direction) at the bottom of the case 41 by a driving mechanism 67.Further, by way of example, the arm 66 can be moved in the verticaldirection by an elevating mechanism included in the driving mechanism67.

By the X-directional movement of the arm 66, the discharge opening 62 ofthe cleaning solution nozzle 6 can be moved from a central area of thewafer W, which is attracted to and held on the wafer holder 44, to aperiphery area of the wafer W in the X direction. Further, the main body61 is fixed at the arm 66 while the discharge opening is slightlyinclined from the X direction toward a rotation direction of the wafer,i.e., a clockwise direction.

The gas nozzle 7 is configured to supply an inert gas onto the surfaceof the wafer W. That is, it blows the inert gas. The gas nozzle 7 hasthe same configuration as the cleaning solution nozzle 6 as depicted inFIGS. 5A, 5B and 6. Further, the gas nozzle 7 has a main body 71, andthe main body 71 is fixed at the arm 76 bent in an L shape as depictedin FIG. 7. The gas nozzle 7 is different from the cleaning solutionnozzle 6 in that the arm 76 can be moved in the X direction and in thevertical direction by a driving mechanism 77 and can also be moved in aforward/backward direction (Y direction). That is, the driving mechanism77 includes an X-directional moving body 77 a and a Y-directional movingbody 77 b. Further, the arm 76 can be moved along the guide rail 57 a inthe X direction by the X-directional moving body 77 a and can be movedalong a forward/backward direction (Y direction) with respect to theX-directional moving body 77 a by the Y-directional moving body 77 b.

In FIG. 7, reference numeral 72 denotes a discharge opening andreference numeral 73 denotes a gas supply line. In FIG. 3, referencenumeral 74 denotes a group of supply devices and reference numeral 75denotes a gas supply source for supplying an inert gas such as anitrogen gas.

The controller 100 includes a computer and a storage unit. As depictedin FIGS. 3 and 4, the controller 100 outputs a control signal forcontrolling the driving mechanisms 57, 67, and 77, the driving unit 44 athat rotates the wafer holder 44, and the groups of supply devices 54,64, and 74 according to a program stored in the non-illustrated storageunit.

Hereinafter, referring to FIG. 8, the line width measurement apparatus110 will be explained. FIG. 8 is a longitudinal cross sectional viewshowing a schematic configuration of the line width measurementapparatus.

The line width measurement apparatus 110 includes, for example, amounting table 111 that horizontally mounts the wafer W thereon and anoptical surface shape measurement device 112 as depicted in FIG. 8. Byway of example, the mounting table 111 is configured as an X-Y stage,and, thus, it can be moved in a two-dimensional direction of ahorizontal direction. The optical surface shape measurement device 112includes, for example, a light irradiation unit 113, a light detectionunit 114, and a calculation unit 115. The light irradiation unit 113irradiates lights to the wafer W in an inclined direction. The lightdetection unit 114 detects lights irradiated from the light irradiationunit 113 and then reflected from the wafer W. The calculation unit 115calculates a line width CD of a resist pattern on the wafer W based oninformation on the received light of the light detection unit 114. Theline width measurement apparatus 110 measures a line width of the resistpattern by using, for example, a scatterometry method. In case of usingthe scatterometry method, the calculation unit 115 compares adistribution of light intensities on the surface of the wafer W detectedby the light detection unit 114 with a virtual distribution of lightintensities previously stored therein. Then, a line width CD of theresist pattern corresponding to the compared virtual distribution oflight intensities is obtained, and, thus, the line width CD of theresist pattern can be measured.

Further, the line width measurement apparatus 110 horizontally moves thewafer W relative to the light irradiation unit 113 and the lightdetection unit 114, so that line widths at multiple measurement pointson the surface of the wafer W can be measured.

By way of example, while a first processing condition such as aprocessing time t of a cleaning process performed by the developing unit(DEV) 28 for each wafer W is being modified, a first patterning processis performed on each wafer W in a wafer set including multiple wafers W.Accordingly, a first-time resist pattern (first resist pattern) P1 isformed. Thereafter, a second pattering process is performed on eachwafer W having thereon the first resist pattern, so that a second-timeresist pattern (second resist pattern) P2 is formed thereon. Then, aline width CD2 of the second resist pattern P2 is measured by the linewidth measurement apparatus 110. By way of example, a measurement resultof the line width measurement apparatus 110 is outputted from thecalculation unit 115 to the main controller 10 to be described later.Consequently, first data showing a relationship between the firstprocessing condition such as the processing time t and the line widthCD2 of the second resist pattern P2 are prepared.

A wafer process performed by the substrate processing system configuredas described above is controlled by the main controller 10 depicted inFIG. 1. The main controller controls the line width measurementapparatus 110 to measure a line width of a resist pattern on the waferW. The main controller 10 includes a general-purpose computer having,for example, a CPU and a memory and controls a wafer process or ameasurement of a line width by executing a program stored therein.Further, the program of the main controller 10 may be installed in themain controller 10 by means of a computer readable storage medium.

Hereinafter, referring to FIGS. 9 to 11A and 11B, a substrate processingmethod using the substrate processing system in accordance with thepresent embodiment will be explained. FIG. 9 is a flow chart forexplaining a sequence of processes of a substrate processing method inaccordance with the present embodiment. FIGS. 10A to 10J are crosssectional views showing a status of a wafer in each process of thesubstrate processing method in accordance with the present embodiment.FIGS. 11A and 11B are plane views showing a status of a wafer in eachprocess of a cleaning process in accordance with the present embodiment.

As depicted in FIG. 9, the substrate processing method in accordancewith the present embodiment includes a data preparation process (stepS11), a first process (steps S11 to S16), and a second process (stepsS17 to S20). The first process (step S12 to S16) includes a firstcoating process (step S12), a first exposure process (step S13), a firstheating process (step S14), a first developing process (step S15), and acleaning process (step S16). The second process (steps S17 to S20)includes a second coating process (step S17), a second exposure process(step S18), a second heating process (step S19), and a second developingprocess (step S20).

First of all, the data preparation process (step S11) is performed. Inthe data preparation process (step S11), first data showing arelationship between a first processing condition under which a cleaningprocess is performed on the wafer W in the cleaning process (step S16)and a space width SP2′ of the second resist pattern P2 are prepared.

The first processing condition may include a processing time t forcleaning the wafer W, a temperature T of the cleaning solution, a flowrate F, and pH. Hereinafter, there will be explained a case where theprocessing time t for cleaning the wafer W is used as the firstprocessing condition.

The first coating process (step S12) to the first developing process(step S15) to be described later are performed on each wafer W of thewafer set including the multiple wafers W. Then, the cleaning process(step S16) to be described later is performed while the processing timet is modified for each wafer W. Thereafter, by performing the secondcoating process (step S17) to the second developing process (step S20)to be described later, the first resist pattern P1 and the second resistpattern P2 are formed on the wafer W as described later with referenceto FIGS. 10A to 10J. Subsequently, the space width SP2′ of the formedsecond resist pattern P2 is measured by the line width measurementapparatus 110. In this way, the first data showing a relationshipbetween the processing time t and the space width SP2′ of the secondresist pattern P2 are prepared.

Further, the space width SP2′ of the second resist pattern P2corresponds to the line width of the second resist pattern of thepresent disclosure.

Then, the first process (step S12 to S16) is performed on a single waferW.

First, the first coating process (step S12) is performed on the singlewafer W. In the first coating process (step S12), a first resist film133 is formed by coating the single wafer W with a resist. FIG. 10Ashows a status of the wafer in the first coating process (step S12).

Prior to the first coating process (step S12), a bottom antireflectionfilm 132 is formed on the wafer 130 (wafer W) on which an etching targetfilm 131 is previously formed.

The carrier C1 in which multiple wafers W are accommodated is loadedinto the carrier mounting unit B1 from the outside; a single sheet ofthe wafer W is taken out from the inside of the carrier C1 by thetransit mechanism A1; and then the wafer W is loaded into the processingunit B2. The wafer W loaded into the processing unit B2 is delivered tothe main transfer mechanism A2 through a transit unit of the rack unitU1. The wafer W delivered to the main transfer mechanism A2 is loadedinto the antireflection film forming unit BARC of the liquid processingunit U4. The bottom antireflection film (BARC) 132 is formed on thewafer 130 (wafer W), on which the etching target film 131 has beenformed, in the antireflection film forming unit BARC.

The wafer 130 (wafer W) on which the bottom antireflection film 132 hasbeen formed is loaded into the coating unit (COT) 27 by the maintransfer mechanism A2 through a delivery unit of the rack unit U2. Thefirst resist film 133 is formed on a top of the bottom antireflectionfilm (BARC) 132 of the wafer 130 (wafer W) loaded into the coating unit(COT) 27.

A resist used for forming the first resist film 133 may be a chemicallyamplified resist. As a specific example, it may be possible to use achemically amplified positive resist which can respond to an exposureusing an ArF excimer laser (wavelength of about 193 nm) as a lightsource in the present embodiment.

Further, a top antireflection film (TARC) may be formed on a top of thefirst resist film 133.

The wafer W on which the first resist film 133 is formed is loaded intothe heating unit of the rack unit U2 and the wafer W is baked at apredetermined temperature. The baked wafer W is cooled by the coolingunit of the rack unit U2 and then loaded into a transit unit of the rackunit U3 by the main transfer mechanism A3. Thus, the first-time coatingprocess is ended.

Subsequently, the first exposure process (step S13) is performed on thesingle wafer W. In the first exposure process (step S13), the singlewafer W on which the first resist film 133 is formed is exposed tolights. FIG. 10B shows a status of the wafer W in the first exposureprocess (step S13).

The wafer W loaded into the transit unit of the rack unit U3 is loadedinto the exposure unit B4 via the first transfer chamber 3A and thesecond transfer chamber 3B by the first substrate transfer unit 31A andthe second substrate transfer unit 31B. Then, the first-time exposureprocess is performed in the exposure unit B4.

In a non-illustrated exposure apparatus within the exposure unit B4, anon-illustrated lens is placed so as to face the surface of the wafer Wat a distance, and pure water is supplied between the lens and thesurface of the wafer W so as to form a liquid film (pure water film).Thereafter, lights from a non-illustrated light source pass through boththe lens and the liquid film and are irradiated to the wafer W, so thata preset circuit pattern is transferred to the resist. Further, presetcircuit patterns are transferred in sequence to the surface of the waferW by repeatedly irradiating lights while transversely sliding theexposure apparatus, and, thus, the circuit patterns are exposed on theentire surface of the wafer W.

When the first-time exposure process is performed, as depicted in FIG.10B, selected areas of the first resist film 133 are exposed to lightsby using a first reticle R1, so that there are formed soluble areas 133a which can be dissolved by a developing solution made of, for example,an alkaline solvent. Since the soluble areas 133 a are formed, the firstpattern P1 includes the soluble areas 133 a soluble in the developingsolution and insoluble areas 133 b insoluble therein in the first resistfilm 133.

Herein, the first pattern P1 is obtained by using the first reticle R1having lines. As depicted in FIG. 10B, a line width L1 and a space widthSP1 of the first pattern P1 can be set to be, for example, about 32 nmand about 32 nm, respectively.

Subsequently, the first heating process (step S14) is performed on thesingle wafer W. In the first heating process (step S14), the singlewafer W is heated. FIG. 10C shows a status of the wafer in the firstheating process (step S14).

The wafer W on which the first-time exposure process has been performedis taken out from the exposure unit B4 by the second substrate transferunit 31B, and water on the surface of the substrate is removed by thesubstrate cleaning apparatus 4, and then the wafer W is loaded into theheating unit PEB of the rack unit U6.

In the heating unit PEB, the transferred wafer W is mounted on anon-illustrated heating plate via a non-illustrated cooling plate andnon-illustrated elevating pins and a heating process (baking processafter the exposure) is performed on the wafer W. After a preset time,the wafer W is separated from the heating plate by the elevating pins,and, thus, the heating process on the wafer W is ended. Thereafter, thewafer W is delivered from the elevating pins to the cooling plate andcooled by the cooling plate, and then the wafer W is transferred to theoutside of the heating unit PEB from the cooling plate.

As the first heating process (step S14) is performed, a part of theinsoluble areas 133 b is changed into the soluble areas 133 a.Therefore, as depicted in FIG. 10C, the line width L1 of the firstpattern P1 is slightly decreased to L1′ and the space width SP1 of thefirst pattern P1 is slightly increased to SP1′.

Then, the first developing process (step S15) and the cleaning process(step S16) are consecutively performed on the single wafer W. FIG. 10Dshows a status of the wafer after the first developing process (stepS15) and the cleaning process (step S16).

The first developing process (step S15) is first performed. In the firstdeveloping process (step S15), the single wafer W on which the firstheating process (step S14) has been performed is developed.

The wafer W on which the first heating process (step S14) has beenperformed is unloaded from the heating unit PEB by the first substratetransfer unit 31A and delivered to the main transfer mechanism A3 viathe transit unit of the rack unit U3. Then, the wafer W is loaded intothe developing unit (DEV) 28 by the main transfer mechanism A3.

In the developing unit (DEV) 28, the shutter 42 is opened and the maintransfer mechanism A3 mounting thereon the wafer W on which thefirst-time heating process has been performed is loaded into the case41. Then, the wafer W on the main transfer mechanism A3 is received byelevating the supporting pins 46 and the received wafer W is deliveredto the wafer holder 44. Subsequently, the main transfer mechanism A3 isretreated and the shutter 42 is closed. The arm 56 is driven such thatthe developing solution nozzle 5 is positioned above a central area ofthe wafer W. Accordingly, a supply position of the developing solutionby the developing solution nozzle 5 is located above a central area,i.e., the center, of the wafer W.

Thereafter, the wafer W is rotated around the vertical shaft, and whilethe developing solution is discharged in a strip-shape through thedischarge opening of the developing solution nozzle 5, the developingnozzle 5 is moved from the central area of the wafer W toward theperiphery area of the wafer W. Thus, the supply position of thedeveloping solution to the wafer W can be moved from the central area ofthe wafer W to the periphery area of the wafer W and the developingsolution is supplied in a spiral shape to the entire surface of thewafer W. By supplying the developing solution to the surface of thewafer W from the developing solution nozzle 5, the first resist film 133on the wafer W is developed. As the developing solution, it may bepossible to use an alkaline solvent such as tetramethyl ammoniumhydroxide (TMAH).

After the first developing process (step S15) is performed as describedabove, the cleaning process (step S16) is performed. In the cleaningprocess (step S16), the processing time t is determined based on thefirst data. For the processing time t, the cleaning process is performedon the single wafer W after the first developing process (step S15), sothat the first resist pattern P1 is formed. Further, in the cleaningprocess (step S16), a cleaning solution supplying process is performedtogether with a gas supplying process. In the cleaning solutionsupplying process, the developed wafer W is rotated, and while a supplyposition of the cleaning solution to the rotating wafer W is being movedfrom the central area toward the periphery area of the wafer W, thecleaning solution is supplied to the wafer W. In the gas supply process,the gas is supplied toward the periphery area of the wafer W at adownstream position of the moving supply position of the cleaningsolution in a rotation direction of the wafer W.

Further, the processing time t includes a time for performing thecleaning solution supplying process. Furthermore, a method ofdetermining the processing time t based on the first data will beexplained later.

To be specific, the developing nozzle 5 is retreated from the wafer W.As depicted in FIG. 11A, the cleaning solution nozzle 6 is positionedsuch that the supply position of the cleaning solution to the wafer Wthrough the cleaning solution nozzle 6 is positioned above the centralarea of the wafer W. At this time, the discharge opening 62 of thecleaning solution nozzle 6 is slightly inclined from the X directiontoward a rotation direction of the wafer W, i.e., a clockwise direction.Further, the gas nozzle 7 is positioned such that a supply position ofthe gas to the wafer W through the gas nozzle 7 is positioned slightlyupstream (right side of FIG. 11A) of the discharge opening 62 in a scandirection of the cleaning solution nozzle 6 and positioned slightlydownstream in a rotation direction of the wafer W. At this time, the gasnozzle 7 is driven by the arm 76. Further, the discharge opening 72 ofthe gas nozzle 7 and the discharge opening 62 of the cleaning solutionnozzle 6 face the same direction.

The wafer W is rotated in a clockwise direction at a rotational speedof, for example, about 500 rpm or less, for example, about 200 rpm, andthe cleaning solution is discharged from the discharge opening 62 of thecleaning solution nozzle 6 at a flow rate of, for example, about 250ml/min. Thus, the cleaning solution is supplied in a thin strip shapeand collides, from an inclined upper area, with the central area of thewafer W including the center thereof. At the same time, a nitrogen gasis blown from the discharge opening 72 of the gas nozzle 7. Since thewafer W is rotated in the clockwise direction, the cleaning solutionsupplied onto the wafer W is influenced by a centrifugal force workingfrom the center to the periphery and a rotatory force working in arotation direction of the wafer W, and, thus, a vortex gas flow isgenerated. A dashed line of FIG. 11A indicates a rice-ear-shaped liquidflow after the cleaning solution is discharged to the center of thewafer W through the cleaning solution nozzle 6 if the gas is not blown.

Meanwhile, if the nitrogen gas is blown through the gas nozzle 7 at aflow rate of, for example, about 5 l/min toward the outside with respectto the liquid flow at a downstream position of the supply position ofthe cleaning solution, the rice-ear-shaped liquid flow is forced to movetoward the periphery area of the wafer W as indicated by a solid line ofFIG. 11A.

In this state, the cleaning solution nozzle 6 moves along the Xdirection at a scan speed of, for example, about mm/sec toward aninjection direction of the cleaning solution, i.e., toward the left sideof FIG. 11A. Further, the gas nozzle 7 also moves in substantially thesame direction and the same speed as the cleaning solution nozzle 6.However, the gas nozzle 7 is moved not only along the X direction, butalso along a slight Y-direction and an injection direction of the gas,i.e., toward the front side by the driving mechanism 77. Thus, thesupply position of the cleaning solution and the supply position of thenitrogen gas become farther apart from each other as they move to theperiphery area of the wafer W.

FIG. 11B shows the cleaning solution nozzle 6 and the gas nozzle 7 whichmove while supplying the cleaning solution and the nitrogen gas,respectively. The liquid flow of the cleaning solution is dischargedfrom the cleaning solution nozzle 6 and extended in a rice-ear shape inthe clockwise direction, and an outward gas flow is blown from the gasnozzle 7 to the liquid flow. Accordingly, the liquid flow of thecleaning solution is forced to move toward the outside while bothnozzles 6 and 7 move toward the periphery area of the wafer W (towardthe outside). Consequently, a ring-shaped coating area 200 of thecleaning solution is formed on the wafer W and an inner circumference ofthe ring, i.e., a dried area 300 spreads toward the outside. In thisway, the cleaning solution nozzle 6 and the gas nozzle 7 scan the waferW to the periphery area of the wafer W.

As described above, the soluble areas 133 a of the first resist film 133are dissolved and removed by performing the first developing process(step S15) and the cleaning process (step S16), and as depicted in FIG.10D., only the insoluble areas 133 b remain and the first resist patternP1 is formed.

After the cleaning process (step S16), the cleaning solution nozzle 6and the gas nozzle 7 are raised and retreat from an upper area of thecup 43. Further, the wafer W on which the cleaning process has beenperformed is unloaded by the main transfer mechanism A3 in the reversesequence to loading of the wafer W. The wafer W unloaded by the maintransfer mechanism A3 is transferred to the heating unit and the coolingunit in sequence and then a preset process such as a post-baking processhas been performed on the wafer W. Then, the single wafer W having firstresist pattern P1 is transferred to the transit unit of the rack unitU1. Thus, the first-time developing process is ended.

Subsequently, the second process (steps S17 to S20) is performed on thesingle wafer W.

The second coating process (step S17) is performed on the single waferW. In the second coating process (step S17), the single wafer W iscoated with a resist, and a second resist film 135 is formed. FIGS. 10Eand 10F show statuses of the wafer in the second coating process (stepS17).

The wafer W within the transit unit of the rack unit U1 is transferredby the main transfer mechanism A2 to a heating unit, a cooling unit, anda curing unit in sequence included in any one of the rack units U1 toU3. Then, a cleaning process and a surface treatment such as a curingprocess using irradiation of ultraviolet lights are performed on thepattern formed by the first-time coating, exposure, developingprocesses. Consequently, it is possible to prevent adhesion of particlesor occurrence of leaching during a second-time coating process. Asdepicted in FIG. 10E, in the first resist pattern P1 on which the curingprocess has been performed, its surface 134 is cured. Then, the wafer Wis returned to the transit unit of the rack unit U1.

Thereafter, the wafer W in the transit unit of the rack unit U1 istransferred by the main transfer mechanism A2 to the coating unit (COT)27, the heating unit, and the cooling unit in sequence, in which presetprocesses are performed. Consequently, as depicted in FIG. 10F, thesecond resist film 135 is formed on the wafer W having the first resistpattern P1.

A resist used for forming the second resist film 135 may be a chemicallyamplified resist, and it may be possible to use a chemically amplifiedpositive resist which can respond to an exposure using an ArF excimerlaser (wavelength of about 193 nm) as a light source. Further, a topantireflection film (TARC) may be formed on a top of the second resistfilm 135.

Then, the wafer W on which the second resist film 135 is formed isloaded into the transit unit of the rack unit U3 by the main transfermechanism A3. Thus, a second-time coating process is ended.

Subsequently, the second exposure process (step S18) is performed on thesingle wafer W. In the second exposure process (step S18), the singlewafer W on which the second resist film 135 is formed is exposed tolights. FIG. 10G shows a status of the wafer W in the second exposureprocess (step S18).

The wafer W loaded into the transit unit of the rack unit U3 is loadedinto the exposure unit B4 via the first transfer chamber 3A and thesecond transfer chamber 3B by the first substrate transfer unit 31A andthe second substrate transfer unit 31B. Then, a second-time exposureprocess is performed in the exposure unit B4.

When the second-time exposure is performed, as depicted in FIG. 10G,selected areas of the second resist film 135 are exposed to lights byusing a second reticle R2, so that there are formed soluble areas 135 awhich can be dissolved by a developing solution made of, for example, analkaline solvent. Since the soluble areas 135 a are formed, the secondpattern P2 includes the soluble areas 135 a soluble in the developingsolution and insoluble areas 135 b insoluble therein in the secondresist film 135.

Herein, the second pattern P2 is obtained by using the second reticle R2having lines. As depicted in FIG. 10G, a line width L2 and a space widthSP2 of the second pattern P2 can be set to be, for example, about 32 nmand about 32 nm, respectively.

Subsequently, the second heating process (step S19) is performed on thesingle wafer W. In the second heating process (step S19), the singlewafer W is heated. FIG. 10H shows a status of the wafer in the secondheating process (step S19).

The wafer W on which the second-time exposure process has been performedis taken out from the exposure unit B4 by the second substrate transferunit 31B, and water on the surface of the substrate is removed by thesubstrate cleaning apparatus 4, and then the wafer W is loaded into theheating unit PEB of the rack unit U6. Thereafter, a second-time heatingprocess is performed in the same manner as the first-time heatingprocess.

As the second heating process (step S19) is performed, a part of theinsoluble areas 135 b is changed into the soluble areas 135 a.Therefore, as depicted in FIG. 10H, the line width L2 of the secondpattern P2 is slightly decreased to L2′ and the space width SP2 of thesecond pattern P2 is slightly increased to SP2′.

Then, the second developing process (step S20) is performed on thesingle wafer W. In the second developing process (step S20), the singlewafer W on which the second heating process (step S19) has beenperformed is developed, and, thus, the second resist pattern P2 isformed. FIG. 10I shows a status of the wafer in the second developingprocess (step S20).

The single wafer W on which the second heating process (step S19) hasbeen performed is unloaded from the heating unit PEB by the firstsubstrate transfer unit 31A; delivered to the main transfer mechanismA3; and loaded into the developing unit (DEV) 28. Then, within thedeveloping unit (DEV) 28, the second resist pattern 135 on the singlewafer W is developed. In the second-time developing process, the solubleareas 135 a of the second resist film 135 are dissolved and removed byan alkaline solvent such as THAH. Consequently, as depicted in FIG. 10I,only the insoluble areas 135 b remain and the second resist pattern P2is formed. After the second developing process (step S20), anon-illustrated second-time cleaning process may be performed.

The wafer W having the second resist pattern P2 is unloaded from thedeveloping unit (DEV) 28 by the main transfer mechanism A3 andtransferred to the heating unit and the cooling unit in sequence andthen a preset process such as a post-baking process is performed on thewafer W. Then, the single wafer W having the second resist pattern P2 istransferred to the transit unit of the rack unit U1. Thus, thesecond-time developing process is ended.

The wafer W, on which the second-time developing process has beenperformed, in the transit unit of the rack unit U1 is returned to thecarrier C1 on the mounting unit 20 a after a line width of a resistpattern is measured by the line width measurement apparatus 110.

Further, as for the wafer W on which the substrate processing methodincluding the second-time developing process in accordance with thepresent embodiment has been performed, the etching target film 131 maybe etched as depicted in FIG. 10J by an etching apparatus installedseparately from the substrate processing system.

Hereinafter, referring to FIG. 12, there will be explained a method ofdetermining a processing time t in the cleaning process (step S16).

FIG. 12 is a graph schematically showing a relationship between aprocessing time and a space width of a second resist pattern.

In a case where the processing time t for the cleaning process (stepS16) is short, the space width SP2′ of the second resist pattern P2after the second heating process (step S19) is smaller than the spacewidth SP2′ in a case where the processing time t is long. This isbecause the developing solution supplied to the wafer W is not removedsufficiently and the developing solution such as an alkaline solventremains on the surface of the wafer W in the first developing process(step S15).

Further, in a case where the processing time t for the cleaning process(step S16) is sufficiently long, even if the processing time t isfurther lengthened, the space width SP2′ of the second resist pattern P2is not changed. This is because the developing solution supplied to thewafer W is approximately completely removed and the developing solutiondoes not remain on the surface of the wafer W in the first developingprocess (step S15).

Therefore, in the relationship between the processing time t and thespace width SP2′ (CD2) of the second resist pattern P2, as theprocessing time t is increased within a short processing time range, thespace width SP2′ (CD2) is increased, and finally saturated to a constantvalue CD0 after a time t1 as depicted in FIG. 12.

Meanwhile, if the line width CD2 of the second resist pattern P2 isdefined as the line width L2′ rather than the space width SP2′, in therelationship between the processing time t and the line width L2′ (CD2)of the second resist pattern P2, as the processing time t is increasedwithin a short processing time range, the line width L2′ (CD2) isdecreased and finally converges to a constant value CD0 after the timet1. That is, in this case, as the processing time t is increased, theline width CD2 is changed and finally converges to the constant valueCD0 after a convergence time t1.

If the processing time t is shorter than the convergence time t1, theline width CD2 of the second resist pattern P2 cannot be the constantvalue CD0 as an original value which can be obtained when a cleaningprocess is performed for a sufficiently long time. Further, if theprocessing time t is shorter than the convergence time t1, the linewidth CD2 is varied depending on the processing time t. Therefore,non-uniformity in the line width CD2 is likely to be increased betweenwafers or within a surface of the single wafer.

Meanwhile, if the processing time t is longer than the convergence timet1, the line width CD2 of the second resist pattern P2 can be theconstant value CD0. Further, if the processing time t is longer than theconvergence time t1, the line width CD2 becomes uniform regardless ofthe processing time t. Therefore, non-uniformity in the line width CD2may be decreased between wafers or within a surface of the single wafer.

In the present embodiment, since the first data has been prepared inadvance, the convergence time t1 can be measured accurately. Therefore,the processing time t is determined to be substantially the same as theconvergence time t1, so that non-uniformity in the line width CD2 of thesecond resist pattern P2 in a wafer surface can be decreased withoutincreasing the processing time t.

Hereinafter, referring to FIGS. 13A and 13B, there will be explained acomparison result of distribution of the line widths CD2 of the secondresist pattern P2 in a wafer surface in the present embodiment and acomparative example 1 where the first data has not been prepared inadvance.

FIGS. 13A and 13B show distribution of space widths of a second resistpattern in a wafer surface obtained by performing substrate processingmethods in accordance with the first embodiment and the comparativeexample 1, respectively. Further, FIGS. 13A and 13B show thedistribution of the space widths represented by a gray scale usingsubstantially the same upper and lower limit values.

In the comparative example 1, as depicted in FIG. 13B, an area having asmall space width SP2′ (line width CD2) (dark area) is observed at acentral area of the wafer W and substantially the same value is notshown over the entire surface of the wafer W. Thus, it is deemed that,in the comparative example 1, a cleaning process is not sufficientlyperformed at the central area of the wafer W.

Meanwhile, in the present embodiment, as depicted in FIG. 13A, an areahaving a small space width SP2′ (line width CD2) (dark area) is notobserved at a central area of the wafer W and substantially the samevalue is shown over the entire surface of the wafer W. Thus, it isdeemed that, in the present embodiment, a cleaning process issufficiently performed at the central area of the wafer W.

Further, non-uniformity CD3σ in the space width SP2′ (line width CD2) ofthe present embodiment is smaller than that of the comparativeexample 1. Therefore, in accordance with the present embodiment,non-uniformity in the space width SP2′ (line width CD2) in a wafersurface can be decreased.

In the cleaning process, if the gas is supplied toward the peripheryarea of the wafer W at the downstream position of the supply position ofthe cleaning solution in the rotation direction of the wafer W, a supplyamount of the cleaning solution is likely to be decreased at the centralarea of the wafer W as compared to the periphery area of the wafer W.Therefore, the present embodiment may have a great effect of decreasingnon-uniformity in the line width CD2 of the second resist pattern P2 ina wafer surface without increasing the processing time t.

In the cleaning process (step S16) in accordance with the presentembodiment, the convergence time t1 can be decreased by increasing atemperature T of the cleaning solution or a flow rate F of the cleaningsolution.

FIGS. 14 to 16 show examples of first data showing a relationshipbetween a processing time and a space width of a second resist patternwhen a temperature or a flow rate of a cleaning solution is varied. FIG.14 shows a case where a temperature of a cleaning solution is about 23°C. and a flow rate thereof is about 350 ml, FIG. 15 shows a case where atemperature of a cleaning solution is about 50° C. and a flow ratethereof is about 350 ml, and FIG. 16 shows a case where a temperature ofa cleaning solution is about 23° C. and a flow rate thereof is about 800ml.

In FIGS. 14 to 16, a processing time t is normalized by substantiallythe same maximum value. Further, a longitudinal axis on the leftrepresents an average (line width average) CDave of the space width SP2′(line width CD2) of the second resist pattern P2 in a wafer surface.Furthermore, a longitudinal axis on the right represents non-uniformity(line width non-uniformity) CD3σ in the space width SP2′ (line widthCD2) of the second resist pattern P2 in a wafer surface.

In FIG. 14, the line width average CDave is increased as the processingtime t is increased, and converges between the normalized processingtime t 0.05 to 1.00. Further, as the processing time t is increased, theline width non-uniformity CD3σ is decreased, and converges between thenormalized processing time t 0.05 to 1.00.

In FIG. 15, the line width average CDave is increased as the processingtime t is increased, and the line width average CDave converges afterthe normalized processing time t of about 0.25. Further, the line widthnon-uniformity CD3σ is decreased as the processing time t is increased,and the line width average CDave converges after the normalizedprocessing time t of about 0.25.

Further, in FIG. 16, the line width average CDave is increased as theprocessing time t is increased, and the line width average CDaveconverges after the normalized processing time t of about 0.25. Further,the line width non-uniformity CD3σ is decreased as the processing time tis increased, and the line width average CDave converges after thenormalized processing time t of about 0.25.

By comparing FIG. 14 with FIG. 15, it can be seen that a convergencetime t1 can be further decreased by increasing a temperature T of thecleaning solution to be higher than a normal temperature, andnon-uniformity in line widths of a second-time resist pattern in a wafersurface can be decreased even if a processing time t is decreased.

Desirably, the temperature T of the cleaning solution may be higher thanthe normal temperature, more desirably, equal to or higher than about30° C.

As described above, by increasing the temperature T of the cleaningsolution to be higher than the normal temperature, the convergence timet1 can be further decreased. The reason for that may be considered asfollows. By way of example, that is because solubility of a remainingdeveloping solution dissolved by a cleaning solution is increased, and,thus, the developing solution can be removed from the surface of thewafer W in a relatively short time.

Further, by comparing FIG. 14 with FIG. 16, it can be seen that aconvergence time t1 can be further decreased by increasing a flow rate Fof the cleaning solution to be relatively high, and non-uniformity inline widths of a second-time resist pattern in a wafer surface can bedecreased even if a processing time t is decreased.

As described above, by increasing the flow rate F of the cleaningsolution to be relatively high, the convergence time t1 can be furtherdecreased. The reason for that may be considered as follows. By way ofexample, that is because a remaining developing solution is mixed with agreater amount of the cleaning solution, and, thus, the developingsolution can be removed from the surface of the wafer W in a relativelyshort time.

To be specific, when the temperature T of the cleaning solution is about23° C. and the flow rate F of the cleaning solution is about 350 ml/min,the convergence time t1 is about 90 seconds, and when the temperature Tof the cleaning solution is about 50° C. and the flow rate F of thecleaning solution is about 550 ml/min, the convergence time t1 is about10 seconds. Thus, by increasing the temperature T of the cleaningsolution to be higher than the normal temperature and increasing theflow rate F of the cleaning solution to be relatively high, theconvergence time t1 can be relatively decreased.

In the cleaning process (step S16), it may be possible to use an acidcleaning solution having a pH of about 7 or less as a cleaning solution.If the acid cleaning solution having a pH of about 7 or less is used asthe cleaning solution, an amount of a developing solution remaining on asurface of a wafer can be reduced in the cleaning process (step S16). Byusing the acid cleaning solution having the pH of about 7 or less, aconvergence time t1 can be further decreased. The reason for that may beconsidered as follows. By way of example, that is because a remainingdeveloping solution is neutralized by the acid cleaning solution, and,thus, the developing solution can be removed from the surface of thewafer W in a relatively short time.

As the acid cleaning solution, it may be possible to select at least oneof inorganic acids and organic acids and to use the at least one as itis or the least one diluted with pure water or the like.

As the inorganic acids, it may be possible to use at least one ofhydrochloric acid, nitric acid, phosphoric acid, sulphuric acid, boricacid, and hydrofluoric acid.

As the organic acids, it may be possible to use at least one of fattyacid (fatty carboxylic acid), aromatic carboxylic acid, and oxocarboxylic acid.

As the fatty acid (fatty carboxylic acid), it may be possible to use atleast one of formic acid [methanoic acid], acetic acid [ethanoic acid],propionic acid [propanoic acid], butyric acid [butanoic acid],isobutyric acid, valeric acid (valerian acid) [pentanoic acid],isovaleric acid, caproic acid [hexanoic acid], enanthic acid (heptylacid) [heptanoic acid], caprylic acid [octanoic acid], pelargonic acid[nonanoic acid], capric acid [decanoic acid], lauric acid [dodecanoicacid], myristic acid [tetradecanoic acid], pentadecylic acid[pentadecanoic acid], palmitic acid (cetanoic acid) [hexadecanoic acid],margaric acid [heptadecanoic acid], stearic acid [octadecanoic acid],oleic acid, linoleic acid, linolenic acid, tuberculostearic acid[nonadecanoic acid], arachidic acid [icosanoic acid], arachidonic acid,eicosapentaenoic acid, behenic acid [docosanoic acid], docosahexaenoicacid, lignoceric acid [tetracosanoic acid], cerotic acid [hexacosanoicacid], montanic acid [octacosanoic acid], and melissic acid[triacontanoic acid)].

As the aromatic carboxylic acid, it may be possible to use at least oneof salicylic acid [hydroxybenzoic acid], gallic acid (trihydroxybenzoicacid), benzoic acid [benzene carboxylic acid], phthalic acid, cinnamicacid (β-phenylacrylic acid), and mellitic acid (mellit acid, graphiticacid) [benzene hexacarboxylic acid].

As the oxo carboxylic acid, it may be possible to use pyruvic acid(oxopropionic acid, α-ketopropionic acid and pyroracemic acid).

Further, as the organic acids, it may be possible to use other kinds oforganic acids. As the other kinds of organic acids, it may be possibleto use at least one of oxalic acid [ethanedioic acid], lactic acid(α-hydroxypropanoic acid), tartaric acid, maleic acid, fumaric acid(fumar acid allomaleic acid, boletic acid, lichenic acid), malonic acid[propanedioic acid], succinic acid, malic acid (hydroxysuccinic acid),citric acid, aconitic acid, glutaric acid, adipic acid [hexanedioicacid], amino acid, and L-ascorbic acid (vitamin C).

As described above, in accordance with the substrate processing methodof the present embodiment, the first data are prepared and theprocessing time t for performing the cleaning process on the wafer W isdetermined based on the first data. Therefore, the processing time t maybe determined such that the processing time t is substantially the sameas the convergence time t1 when the line width CD2 of the second resistpattern P2 converges. Thus, it is possible to decrease non-uniformity inline widths of the second-time resist pattern in a wafer surface withoutincreasing a processing time.

First Modification Example of First Embodiment

Hereinafter, referring to FIGS. 17 and 18, there will be explained asubstrate processing method in accordance with a first modificationexample of the first embodiment.

A substrate processing method of the present modification example isdifferent from the substrate processing method in accordance with thefirst embodiment in that a processing time t is determined based on arelationship between the processing time t and line widths CD2-1 andCD2-2 of a second resist pattern P2 on both a central area of a wafer Wand a periphery area of the wafer W.

In this modification example, the substrate processing system, thedeveloping unit, and the line width measurement apparatus explained inthe first embodiment may be used.

FIG. 17 is a flow chart for explaining a sequence of processes of asubstrate processing method in accordance with the present modificationexample. FIG. 18 is a graph schematically showing a relationship betweena processing time and a space width of a second resist pattern.

As depicted in FIG. 17, the substrate processing method in accordancewith the present modification example includes a data preparationprocess (step S31), a first process (step S32 to step S36), and a secondprocess (step S37 to step S40). The first process (step S32 to step S36)includes a first coating process (step 32), a first exposure process(step S33), a first heating process (step S34), a first developingprocess (step S35), and a cleaning process (step S36). The secondprocess (step S37 to step S40) includes a second coating process (stepS37), a second exposure process (step S38), a second heating process(step S39), and a second developing process (step S40).

First of all, the data preparation process (step S31) is performed. Inthe data preparation process (step S31), first and second data showing arelationship between a processing time t for performing a cleaningprocess on the wafer W in the cleaning process (step S36) and spacewidths SP2′ of a second resist pattern P2 formed on a central area ofthe wafer W and a periphery area of the wafer W.

The first coating process (step S32) to the first developing process(step S35) are performed on each wafer W of a wafer set includingmultiple wafers W. Then, the cleaning process (step S36) is performedwhile the processing time t is varied for each wafer W. Thereafter, byperforming the second coating process (step S37) to the seconddeveloping process (step S40) to be described later, a first resistpattern P1 and a second resist pattern P2 are formed on the wafer W asdescribed in the first embodiment with reference to FIGS. 10A to 10J.Subsequently, the space widths SP2′-1 and SP2′-2 of the second resistpattern P2 formed on the central area of the wafer W and the peripheryarea of the wafer W are measured by the line width measurement apparatus110. In this way, the first data and the second data showing arelationship between the processing time t and the space widths SP2′-1and SP2′-2 of the second resist pattern P2 formed on the central area ofthe wafer W and the periphery area of the wafer W are prepared.

Further, the space widths SP2′-1 and SP2′-2 of the second resist patternP2 correspond to the line widths of the second resist pattern of thepresent disclosure.

Then, the first process (step S32 to step S36) is performed on a singlewafer W. Each of the first coating process (step S32) to the firstdeveloping process (step S35) is the same as each of the first coatingprocess (step S12) to the first developing process (step S15). Further,the cleaning process (step S36) is the same as the first cleaningprocess (step S16) of the first embodiment except that the processingtime t is determined based on the first data and the second data.Furthermore, a method of determining the processing time t in thecleaning process (step S36) will be explained later.

Thereafter, the second process (step S37 to step S40) is performed onthe single wafer W. The second process (step S37 to step S40) is thesame as the second process (step S17 to step S20) of the firstembodiment.

Hereinafter, a method of determining the processing time t in thecleaning process (step S36) will be explained.

As explained in the first embodiment, as the processing time t isincreased within a short processing time range, the space width SP2′(CD2) of the second resist pattern P2 is changed, and finally saturatedto a constant value CD0 after a certain time.

However, a supply speed of the cleaning solution in the cleaning processis different between the central area of the wafer W and the peripheryarea of the wafer W, and, thus, the space widths SP2′ (CD2) converges tothe constant value CD0 at different times. In the present modificationexample, in the same manner as the first embodiment, while the cleaningsolution is supplied, a gas is supplied toward the periphery area of thewafer W at a downstream position of a supply position of the cleaningsolution in a rotation direction of the wafer W. Therefore, the spacewidth SP2′ (CD2) on the periphery area of the wafer W converges to theconstant value CD0 in a shorter time than the space width SP2′ (CD2) onthe central area of the wafer W. That is, as depicted in FIG. 18, thespace width SP2′ (CD2) on the central area of the wafer W converges tothe constant value CD0 after a convergence time t1 and the space widthSP2′ (CD2) on the periphery area of the wafer W converges to theconstant value CD0 after a convergence time t2 (<t1).

If the processing time t is shorter than the convergence time t2, theline widths CD2 of the second resist pattern P2 on both the central areaand the periphery area of the wafer W cannot be the constant value CD0and non-uniformity in the line width CD2 cannot be decreased betweenwafers or in a single wafer surface.

Meanwhile, if the processing time t is longer than the convergence timet2 on the periphery area and shorter than the convergence time t1 on thecentral area, the line width CD2 on the periphery area of the wafer Wcan be the constant value CD0 and non-uniformity in the line width CD2can be decreased between wafers or in a single wafer surface. However,the line width CD2 of the second resist pattern P2 on the central areaof the wafer W cannot be the constant value CD0 and non-uniformity inthe line width CD2 cannot be decreased between wafers or in a singlewafer surface.

If the processing time t is longer than the convergence time t1, theline widths CD2 on both the central area of the wafer W and theperiphery area of the wafer W can be the constant value CD0 andnon-uniformity in the line width CD2 can be decreased between wafers orwithin a surface of the single wafer.

Therefore, the first data (convergence time t1) and the second data(convergence time t2) are prepared and the processing time t isdetermined to be substantially the same as any longer one of theconvergence time t1 and the convergence time 2, so that non-uniformityin a line width CD2-1 (space width SP2′-1) and a line width CD2-2 (spacewidth SP2′-2) within a surface of the single wafer can be decreasedwithout increasing the processing time t.

In the present modification example, there has been explained a casewhere a wafer is divided into two areas including a central area and aperiphery area of the wafer; data showing a relationship between theprocessing time t and the line widths of the second resist pattern foreach area are prepared; and the processing time t is determined based onthe data. However, the number of the divided areas of the wafer is notlimited to two, but the wafer may be divided into three or more areas;data showing a relationship between the processing time t and the linewidths of the second resist pattern for each of the areas are prepared;and the processing time t may be determined based on the data. Thus,non-uniformity in the line widths of the second resist pattern can befurther decreased between wafers and in a surface of the single wafer.

Second Modification Example of First Embodiment

Hereinafter, referring to FIGS. 19 to 22, there will be explained asubstrate processing method in accordance with a second modificationexample of the first embodiment.

The substrate processing method in accordance with the presentmodification example is different from the substrate processing methodof the first embodiment in that first data include a first processingcondition under which a cleaning process is performed on the wafer W inthe first process and the first data show a relationship between acondition other than a processing time and a line width CD2 of a secondresist pattern P2.

In the present modification example, the substrate processing system,the developing unit, and the line width measurement apparatus explainedin the first embodiment may be used.

FIG. 19 is a flow chart for explaining a sequence of processes of thesubstrate processing method in accordance with the present modificationexample.

As depicted in FIG. 19, the substrate processing method in accordancewith the present modification example includes a data preparationprocess (step S111) to a second developing process (step S120). Each ofa first coating process (step S112) to a first developing process (stepS115) is the same as each of the first coating process (step S12) to thefirst developing process (step S15) explained with reference to FIG. 9,and, thus, explanation thereof will be omitted. Further, each of asecond coating process (step S117) to the second developing process(step S120) is the same as each of the second coating process (step S17)to the second developing process (step S20) explained with reference toFIG. 9, and, thus, explanation thereof will be omitted.

First of all, in the data preparation process (step S111), first datashowing a relationship between a first processing condition under whicha cleaning process is performed on the wafer W in the cleaning process(step S116) and a space width SP2′ of a second resist pattern P2 areprepared.

The first coating process (step S112) to the first developing process(step S115) are performed on each wafer W of a wafer set includingmultiple wafers W. Then, the cleaning process (step S116) is performedwhile the first processing condition is modified for each wafer W.Thereafter, by performing the second coating process (step S117) to thesecond developing process (step S120), a first resist pattern P1 and asecond resist pattern P2 are formed on the wafer W as described in thefirst embodiment with reference to FIGS. 10A to 10J. Subsequently, thespace width SP2′ of the second resist pattern P2 formed on the wafer Wis measured by the line width measurement apparatus 110. In this way,the first data showing the relationship between the first processingcondition and the space width SP2′ of the second resist pattern P2 areprepared.

Then, the first process (step S112 to step S116) is performed on asingle wafer W. Each of the first coating process (step S112) to thefirst developing process (step 5115) is the same as each of the firstcoating process (step S12) to the first developing process (step S15).Further, the cleaning process (step S116) is the same as the firstcleaning process (step S16) of the first embodiment except that thefirst processing condition is determined based on the first data.

Thereafter, the second process (step S117 to step S120) is performed onthe single wafer W. The second process (step S117 to step S120) is thesame as the second process (step S17 to step S20) of the firstembodiment.

Hereinafter, some examples of the first processing condition and amethod of determining the first processing condition in the cleaningprocess (step S116) will be explained.

A first example of the first processing condition may be a temperature Tof a cleaning solution. When the temperature T of the cleaning solutionis lower than a first temperature T1, the space width SP2′ of the secondresist pattern P2 varies depending on the temperature T of the cleaningsolution. If the temperature T of the cleaning solution is equal to orhigher than the first temperature T1, the space width SP2′ of the secondresist pattern P2 converges to a constant value. In this case, the firstdata may include the first temperature T1. Further, in the cleaningprocess (step S116), the temperature T of the cleaning solution isdetermined to be substantially the same as the first temperature T1based on the first data.

FIG. 20 is a graph schematically showing a relationship between atemperature of a cleaning solution and a space width of a second resistpattern.

In the cleaning process (step S116), when the temperature T of thecleaning solution is lower than the first temperature T1, the spacewidth SP2′ of the second resist pattern P2 after the second heatingprocess (step S119) is decreased as the temperature T of the cleaningsolution is lowered. That is because, by way of example, a developingsolution supplied to the wafer W is not removed sufficiently and thedeveloping solution such as an alkaline solvent remains on a surface ofthe wafer W in the first developing process (step S115).

Further, in a case where the temperature T of the cleaning solution isequal to or higher than the first temperature T1 in the cleaning process(step S116), even if the temperature T of the cleaning solution isfurther increased, the space width SP2′ of the second resist pattern P2is not changed. That is because, by way of example, the developingsolution supplied to the wafer W is approximately completely removed andthe developing solution does not remain on the surface of the wafer W inthe first developing process (step S115).

As described above, that is because, by way of example, as thetemperature T of the cleaning solution is increased, solubility of aremaining developing solution dissolved by the cleaning solution isincreased, and, thus, the developing solution can be removedsufficiently from the surface of the wafer W.

As depicted in FIG. 20, when the temperature T of the cleaning solutionis lower than the first temperature T1, the space width SP2′ (CD2) isincreased as the temperature T of the cleaning solution is increased andconverges to a constant value CD0 at the first temperature T1. Further,when the temperature T of the cleaning solution becomes equal to orhigher than the first temperature T1, the line width CD2 of the secondresist pattern P2 can be the constant value CD0 and non-uniformity inthe line width CD2 may be decreased between wafers W or in the surfaceof the single wafer.

A second example of the first processing condition may be a flow rate Fof the cleaning solution. If the flow rate F of the cleaning solution islower than a first flow rate F1, the space width SP2′ of the secondresist pattern P2 varies depending on the flow rate F of the cleaningsolution. If the flow rate F of the cleaning solution is equal to orhigher than the first flow rate F1, the space width SP2′ of the secondresist pattern P2 converges to a constant value. In this case, the firstdata may include the first flow rate F1. Further, in the cleaningprocess (step S116), the flow rate F of the cleaning solution isdetermined to be substantially the same as the first flow rate F1 basedon the first data.

FIG. 21 is a graph schematically showing a relationship between a flowrate of a cleaning solution and a space width of a second resistpattern.

In the cleaning process (step S116), if the flow rate F of the cleaningsolution is lower than the first flow rate F1, the space width SP2′ ofthe second resist pattern P2 after the second heating process (stepS119) is decreased as the flow rate F of the cleaning solution islowered. That is because, by way of example, a developing solutionsupplied to the wafer W is not removed sufficiently and the developingsolution as an alkaline solvent remains on the surface of the wafer W inthe first developing process (step S115).

Further, in a case where the flow rate F of the cleaning solution isequal to or higher than the first flow rate F1 in the cleaning process(step S116), even if the flow rate F of the cleaning solution is furtherincreased, the space width SP2′ of the second resist pattern P2 is notchanged. That is because, by way of example, the developing solutionsupplied to the wafer W is approximately completely removed and thedeveloping solution does not remain on the surface of the wafer W in thefirst developing process (step S115).

As described above, that is because, by way of example, as the flow rateF of the cleaning solution is increased, a remaining developing solutionis mixed with a greater amount of the cleaning solution, and, thus, thedeveloping solution can be removed sufficiently from the surface of thewafer W. Further, that is because a part of the insoluble areas 135 b ischanged into the soluble areas 135 a in the second heating process (stepS119) without prevention by remaining components of the developingsolution.

As depicted in FIG. 21, if the flow rate F of the cleaning solution islower than the first flow rate F1, the space width SP2′ (CD2) isincreased as the flow rate F of the cleaning solution is increased andconverges to a constant value CD0 at the first flow rate F1. Further, ifthe flow rate F of the cleaning solution becomes equal to or higher thanthe first flow rate F1, the line width CD2 of the second resist patternP2 can be the constant value CD0 and non-uniformity in the line widthCD2 may be decreased between wafers W or in a single wafer surface.

A third example of the first processing condition may be a pH of thecleaning solution. If the pH of the cleaning solution is higher than afirst pH, the space width SP2′ of the second resist pattern P2 variesdepending on the pH of the cleaning solution. If the pH of the cleaningsolution is equal to or lower than the first pH, the space width SP2′ ofthe second resist pattern P2 converges to a constant value. In thiscase, the first data may include the first pH. Further, in the cleaningprocess (step S116), the pH of the cleaning solution is determined to besubstantially the same as the first pH based on the first data.

FIG. 22 is a graph schematically showing a relationship between a pH ofa cleaning solution and a space width of a second resist pattern.

In the cleaning process (step S116), if the pH of the cleaning solutionis higher than the first pH, the space width SP2′ of the second resistpattern P2 after the second heating process (step S119) is decreased asthe pH of the cleaning solution is increased. That is because, by way ofexample, a developing solution supplied to the wafer W is not removedsufficiently and the developing solution as an alkaline solvent remainson a surface of the wafer W in the first developing process (step S115).

Further, in a case where the pH of the cleaning solution is equal to orlower than the first pH in the cleaning process (step S116), even if thepH of the cleaning solution is further decreased, the space width SP2′of the second resist pattern P2 is not changed. That is because, by wayof example, the developing solution supplied to the wafer W isapproximately completely removed and the developing solution does notremain on the surface of the wafer W in the first developing process(step S115).

As described above, that is because, by way of example, as the pH of thecleaning solution is decreased, a remaining developing solution isneutralized by a cleaning solution having stronger acidity, and, thus,the developing solution can be removed sufficiently from the surface ofthe wafer W.

As depicted in FIG. 22, if the pH of the cleaning solution is higherthan the first pH, the space width SP2′ (CD2) is increased as the pH ofthe cleaning solution is increased and converges to a constant value CD0at the first pH. Further, if the pH of the cleaning solution becomesequal to or lower than the first pH, the line width CD2 of the secondresist pattern P2 can be the constant value CD0 and non-uniformity inthe line width CD2 may be decreased between wafers W or in a singlewafer surface.

By way of example, as an acid cleaning solution having a pH of about 7or less, it may be possible to use at least one of acids mentioned inthe first embodiment as it is or at least one of acids diluted withwater or the like.

In accordance with the present modification example, even if aprocessing time cannot be further reduced due to other limitations on asubstrate processing, the line width CD2 of the second resist pattern P2can be the constant value CD0 by controlling the temperature T, flowrate F, and pH of the cleaning solution and non-uniformity in the linewidths CD2 may be decreased between wafers W and in a single wafersurface.

Further, also in the present modification example, the first processingcondition may be determined based on a relationship between the firstprocessing condition and the line widths CD2-1 and CD2-2 of the secondresist pattern on the central area of the wafer W and the periphery areaof the wafer W, respectively as described in the first modificationexample of the first embodiment. Thus, non-uniformity in the line widthCD2-1 (space width SP2′-1) and the line width CD2-2 (space width SP2′-2)on the central area of the wafer W and the periphery area of the waferW, respectively, can be decreased.

Third Modification Example of First Embodiment

Hereinafter, referring to FIGS. 23 to 26, there will be explained asubstrate processing method in accordance with a third modificationexample of the first embodiment.

The substrate processing method in accordance with the presentmodification example is different from the substrate processing methodof the first embodiment in that first data show a relationship between aprocessing time t, a second processing condition under which a cleaningprocess is performed on the wafer W in a first cleaning process and aline width CD2 of a second resist pattern P2.

Also in the present modification example, the substrate processingsystem, the developing unit, and the line width measurement apparatusexplained in the first embodiment may be used.

FIG. 23 is a flow chart for explaining a sequence of processes of thesubstrate processing method in accordance with the present modificationexample.

As depicted in FIG. 23, the substrate processing method in accordancewith the present modification example includes a data preparationprocess (step S131) to a second developing process (step S140). Each ofa first coating process (step S132) to a first developing process (stepS135) is the same as each of the first coating process (step S12) to thefirst developing process (step S15) explained with reference to FIG. 9,and, thus, explanation thereof will be omitted. Further, each of asecond coating process (step S137) to the second developing process(step S140) is the same as each of the second coating process (step S17)to the second developing process (step S20) explained with reference toFIG. 9, and, thus, explanation thereof will be omitted.

First of all, in the data preparation process (step S131), first datashowing a relationship between a processing time t, a second processingcondition under which a cleaning process is performed on the wafer W ina cleaning process (step S136) and a space width SP2′ of a second resistpattern P2 are prepared. The processing time t and the second conditionis determined based the prepared first data.

The first coating process (step S132) to the first developing process(step S135) are performed on each wafer W of a wafer set includingmultiple wafers W. Then, the cleaning process (step S136) is performedwhile the processing time t and the second processing condition aremodified for each wafer W. Thereafter, by performing the second coatingprocess (step S137) to the second developing process (step S140), afirst resist pattern P1 and a second resist pattern P2 are formed on thewafer W as described in the first embodiment with reference to FIGS. 10Ato 10J. Subsequently, the space width SP2′ of the second resist patternP2 is measured by the line width measurement apparatus 110. In this way,the first data showing the relationship between the processing time t,the second processing condition and the space width SP2′ of the secondresist pattern P2 are prepared.

Then, the first process (step S132 to step S136) is performed on asingle wafer W. Each of the first coating process (step S132) to thefirst developing process (step S135) is the same as each of the firstcoating process (step S12) to the first developing process (step S15).Further, the cleaning process (step S136) is the same as the firstcleaning process (step S16) of the first embodiment except that thecleaning process (step S136) adopts the processing time t and the secondprocessing condition under which the cleaning process is performed onthe single wafer.

Thereafter, the second process (step S137 to step S140) is performed onthe single wafer W. The second process (step S137 to step S140) is thesame as the second process (step S17 to step S20) of the firstembodiment.

Hereinafter, a method of determining the processing time t and thesecond processing condition in the data preparation process (step S131)will be explained.

In the data preparation process (step S131), a method of changing theprocessing time t and the second processing condition for each wafer Wis not limited.

By way of example, when the data preparation process (step S131) isfirst performed, there are prepared the first data corresponding tomatrix condition data in which the processing time t and the secondprocessing conditions are varied, and the processing time t and thesecond processing condition may be determined based on the preparedfirst data.

Further, for each of multiple different second processing conditions, aconvergence time t1 when the space width SP2′ of the second resistpattern P2 converges may be obtained. In this case, the first data mayinclude the multiple different second processing conditions and theconvergence time t1 corresponding to each of the second processingconditions.

Alternatively, the processing time t is fixed to a first processing timet11. In such a state the second processing condition may be optimized toan optimum value such that the space width SP2′ of the second resistpattern P2 converges to the constant value. Further, in a state that thesecond processing condition is optimized to the optimum value, theconvergence time t1 when the space width SP2′ of the second resistpattern P2 converges to the constant value may be obtained. In thiscase, the first data may include the optimum value of the secondprocessing condition and the convergence time t1. There will beexplained a case where the first data include the optimum value of thesecond processing condition and the convergence time t1 afterexplanation of examples of the second processing condition.

A first example of the second processing condition may be a temperatureT of a cleaning solution. In case that the processing time t is set tobe the first processing time t11, if the temperature T of the cleaningsolution is lower than a first temperature T1, the space width SP2′ ofthe second resist pattern P2 varies depending on the temperature T ofthe cleaning solution. If the temperature T of the cleaning solution isequal to or higher than the first temperature T1, the space width SP2′of the second resist pattern P2 converges to a constant value. In thiscase, the first data may include the first temperature T1. In addition,when the temperature T of the cleaning solution is the first temperatureT1, the first data includes the convergence time t1 when the space widthSP2′ of the second resist pattern P2 converges to the constant value.Further, in the data preparation process (step S131), the temperature Tof the cleaning solution is determined to be substantially the same asthe first temperature T1 based on the first data, and the processingtime t is determined to be substantially the same as the convergencetime t1.

FIG. 24 is a graph schematically showing a relationship between aprocessing time, a temperature of a cleaning solution and a space widthof a second resist pattern.

As depicted in FIG. 24, a horizontal axis represents a processing time tand a vertical axis represents a temperature T of the cleaning solution.In an area I where the processing time t is short and the temperature Tof the cleaning solution is low, as the processing time t is decreasedor the temperature T of the cleaning solution is decreased, the spacewidth SP2′ of the second resist pattern P2 becomes narrower. Meanwhile,in an area II where the processing time t is long and the temperature Tof the cleaning solution is high, even if the processing time t isincreased or the temperature T of the cleaning solution is increased,the space width SP2′ of the second resist pattern P2 is not changed andconverges to a constant value CD0. That is, the space width SP2′ of thesecond resist pattern P2 becomes uniform in the area II.

Therefore, if the processing time t is the first time t11 (on a lineL1), and if the temperature T of the cleaning solution is lower than thefirst temperature T1, the space width SP2′ of the second resist patternP2 varies depending on the temperature T of the cleaning solution. Ifthe temperature T of the cleaning solution is equal to or higher thanthe first temperature T1, the space width SP2′ of the second resistpattern P2 converges to a constant value. The first temperature T1 inthis case is obtained. Then, if the temperature T of the cleaningsolution is the first temperature T1 (on a line L2), the convergencetime t1 when the space width SP2′ of the second resist pattern P2converges to a constant value is obtained.

Consequently, the space width SP2′ (CD2) of the second resist pattern P2can be the constant value CD0, and non-uniformity in the line widths CD2may be decreased between wafers W or in a single wafer surface. Further,by varying the temperature T of the cleaning solution, the convergencetime t1 can be further decreased.

A second example of the second processing condition may be a flow rate Fof a cleaning solution. If the processing time t is set to be the firstprocessing time t11, if the flow rate F of the cleaning solution islower than a first flow rate F1, the space width SP2′ of the secondresist pattern P2 varies depending on the flow rate F of the cleaningsolution. If the flow rate F of the cleaning solution is equal to orhigher than the first flow rate F1, the space width SP2′ of the secondresist pattern P2 converges to a constant value. In this case, the firstdata may include the first flow rate F1. Further, when the flow rate Fof the cleaning solution is the first flow rate F1, the first data mayinclude the convergence time t1 when the space width SP2′ of the secondresist pattern P2 converges to the constant value. Furthermore, in thedata preparation process (step S131), the flow rate F of the cleaningsolution is determined to be substantially the same as the first flowrate F1 based on the first data, and the processing time t is determinedto be substantially the same as the convergence time t1.

FIG. 25 is a graph schematically showing a relationship between aprocessing time, a flow rate of a cleaning solution and a space width ofa second resist pattern.

As depicted in FIG. 25, a horizontal axis represents a processing time tand a vertical axis represents a flow rate F of the cleaning solution.In an area I where the processing time t is short and the flow rate F ofthe cleaning solution is low, as the processing time t is decreased orthe flow rate F of the cleaning solution becomes decreased, the spacewidth SP2′ of the second resist pattern P2 is narrower. Meanwhile, in anarea II where the processing time t is long and the flow rate F of thecleaning solution is high, even if the processing time t is increased orthe flow rate F of the cleaning solution is increased, the space widthSP2′ of the second resist pattern P2 is not changed and converges to aconstant value CD0. That is, the space width SP2′ of the second resistpattern P2 becomes uniform in the area II.

Therefore, if the processing time t is the first time t11 (on a lineL1), and if the flow rate F of the cleaning solution is lower than thefirst flow rate F1, the space width SP2′ of the second resist pattern P2varies depending on the flow rate F of the cleaning solution. If theflow rate F of the cleaning solution is equal to or higher than thefirst flow rate F1, the space width SP2′ of the second resist pattern P2converges to a constant value. The first flow rate F1 in this case isobtained. Then, if the flow rate F of the cleaning solution is the firstflow rate F1 (on a line L2), the convergence time t1 when the spacewidth SP2′ of the second resist pattern P2 converges to a constant valueis obtained.

Consequently, the space width SP2′ (CD2) of the second resist pattern P2can be the constant value CD0, and non-uniformity in the line widths CD2may be decreased between wafers W or in a wafer surface. Further, byvarying the flow rate F of the cleaning solution, the convergence timet1 can be further decreased.

A third example of the second processing condition may be a pH of acleaning solution. In case that the processing time t is set to be thefirst processing time t11, if the pH of the cleaning solution is higherthan a first pH, the space width SP2′ of the second resist pattern P2varies depending on the pH of the cleaning solution. If the pH of thecleaning solution is equal to or lower than the first pH, the spacewidth SP2′ of the second resist pattern P2 converges to a constantvalue. In this case, the first data may include the first pH. Further,when the pH of the cleaning solution is the first pH, the first data mayinclude the convergence time t1 when the space width SP2′ of the secondresist pattern P2 converges to the constant value. Furthermore, in thedata preparation process (step S131), the pH of the cleaning solution isdetermined to be substantially the same as the first pH based on thefirst data, and the processing time t is determined to be substantiallythe same as the convergence time t1.

If the first pH is, for example, about 7 and if the processing time t isset to be the first time t11, when a pH of the cleaning solution ishigher than the first pH, i.e., alkaline, the space width SP2′ of thesecond resist pattern P2 varies depending on the pH of the cleaningsolution. Further, when a pH of the cleaning solution is equal to orlower than the first pH, i.e., acid, the space width SP2′ of the secondresist pattern P2 converges to a constant value.

FIG. 26 is a graph schematically showing a relationship between aprocessing time, a pH of a cleaning solution and a space width of asecond resist pattern.

As depicted in FIG. 26, a horizontal axis represents a processing time tand a vertical axis represents a pH of the cleaning solution. In an areaI where the processing time t is short and the pH of the cleaningsolution is high, as the processing time t is decreased or the pH of thecleaning solution is increased, the space width SP2′ of the secondresist pattern P2 becomes narrower. Meanwhile, in an area II where theprocessing time t is long and the pH of the cleaning solution is low,even if the processing time t is increased or the pH of the cleaningsolution is decreased, the space width SP2′ of the second resist patternP2 is not changed and converges to a constant value CD0. That is, thespace width SP2′ of the second resist pattern P2 becomes uniform in thearea II.

Therefore, if the processing time t is the first time t11 (on a lineL1), and if the pH of the cleaning solution is higher than the first pH,the space width SP2′ of the second resist pattern P2 varies depending onthe pH of the cleaning solution. If the pH of the cleaning solution isequal to or lower than the first pH, the space width SP2′ of the secondresist pattern P2 converges to a constant value. The first pH in thiscase is obtained. Then, if the pH of the cleaning solution is the firstpH (on a line L2), the convergence time t1 when the space width SP2′ ofthe second resist pattern P2 converges to a constant value is obtained.

Consequently, the space width SP2′ (CD2) of the second resist pattern P2can be the constant value CD0, and non-uniformity in the line widths CD2may be decreased between wafers W or in a single wafer surface. Further,by varying the pH of the cleaning solution, the convergence time t1 canbe further decreased.

By way of example, as an acid cleaning solution having a pH of about 7or less, it may be possible to use at least one of acids mentioned inthe first embodiment as it is or at least one of acids diluted withwater or the like.

Fourth Modification Example of First Embodiment

Hereinafter, referring to FIG. 27, there will be explained a substrateprocessing method in accordance with a fourth modification example ofthe first embodiment

The substrate processing method in accordance with the presentmodification example is different from the substrate processing methodof the first embodiment in that the present modification exampleincludes an acid processing solution process in which a wafer W isprocessed by an acid processing solution after the first process andbefore the second process.

Also in the present modification example, the substrate processingsystem, the developing unit, and the line width measurement apparatusexplained in the first embodiment may be used.

However, in the present modification example, the cleaning solutionnozzle 6 explained with reference to FIGS. 5A and 5B may be connectedwith a non-illustrated acid processing solution supply source via anon-illustrated processing solution supply line. Alternatively, anon-illustrated acid processing solution nozzle may be providedseparately from the cleaning solution nozzle 6, and the acid processingsolution nozzle may be connected with the non-illustrated acidprocessing solution supply source via the non-illustrated processingsolution supply line.

FIG. 27 is a flow chart for explaining a sequence of processes of thesubstrate processing method in accordance with the present modificationexample.

As depicted in FIG. 27, the substrate processing method in accordancewith the present modification example includes a data preparationprocess (step S151) to a second developing process (step S161). Each ofdata preparation process (step S151) to a cleaning process (step S156)is the same as each of the data preparation process (step S11) to thecleaning process (step S16) explained with reference to FIG. 9, and,thus, explanation thereof will be omitted. Further, each of a secondcoating process (step S158) to the second developing process (step S161)is the same as each of the second coating process (step S17) to thesecond developing process (step S20) explained with reference to FIG. 9,and, thus, explanation thereof will be omitted.

In the present modification example, after the cleaning process (stepS156), an acid processing solution process (step S157) is performedbefore the second coating process (step S158). By way of example, in theacid processing solution process, the wafer W is processed by an acidprocessing solution having a pH of about 7 or less.

By way of example, as the acid processing solution having the pH of 7 orless, it may be possible to use various kinds of acids mentioned in thefirst embodiment.

For example, the acid processing solution may be supplied to the wafer Was follows. If the cleaning solution nozzle 6 is connected with the acidprocessing solution supply source via the processing solution supplyline, the acid processing solution may be supplied to the wafer W fromthe acid processing solution supply source via the cleaning solutionnozzle 6, and, thus, the wafer W may be processed by the acid processingsolution. Alternatively, if the acid processing solution nozzle providedseparately from the cleaning solution nozzle 6 is connected with theacid processing solution supply source via the processing solutionsupply line, the acid processing solution may be supplied to the wafer Wfrom the acid processing solution supply source via the acid processingsolution nozzle, and, thus, the wafer W may be processed by the acidprocessing solution.

In the acid processing solution process (step S157), the acid processingsolution having the pH of 7 or less is used, and, thus, an amount of adeveloping solution remaining on a surface of the wafer W can bereduced, and a part of the insoluble areas 135 b is changed into thesoluble areas 135 a in a second heating process (step S160).Consequently, the space width SP2′ (CD2) of the second resist pattern P2can be the constant value CD0 and non-uniformity in the line widths CD2can be decreased between wafers W or in a single wafer surface. Besides,the convergence time t can be further decreased.

Second Embodiment

Hereinafter, referring to FIGS. 28 to 29E, there will be explained asubstrate processing method in accordance with a second embodiment.

The substrate processing method in accordance with the presentembodiment is different from the substrate processing method inaccordance with the first embodiment in that during a cleaning process,a cleaning solution is supplied to an entire surface of a wafer W andthen a drying of the cleaning solution is started at a central area ofthe wafer W.

Also in the present embodiment, the substrate processing system, thedeveloping unit, and the line width measurement apparatus explained inthe first embodiment may be used.

However, in the present embodiment, instead of the cleaning solutionnozzle 6 having the slit-shaped discharge opening 62 explained withreference to FIGS. 5A and 5B, a cylindrical cleaning solution nozzle 6 amay be used. FIGS. 29A to 29E show the state that the cleaning solutionis supplied to the wafer W through the cylindrical cleaning solutionnozzle 6 a.

Further, in the present embodiment, the developing unit explained withreference to FIGS. 4, 5A and 5B may not include the gas nozzle.

FIG. 28 is a flow chart for explaining a sequence of processes of acleaning process of a substrate processing method in accordance with thepresent embodiment. FIGS. 29A to 29E are perspective views showing astatus of a wafer in each process of the cleaning process in the presentembodiment.

The substrate processing method in accordance with the presentembodiment is the same as the substrate processing method in accordancewith the first embodiment except the cleaning process (step S16).Therefore, explanation of other processes (step S11 to step S15 and stepS17 to step S20) than the cleaning process will be omitted.

The cleaning process of the substrate processing method in accordancewith the present embodiment includes a first cleaning solution supplyprocess (step S51), a second cleaning solution supply process (stepS52), a supply stop process (step S53), and a drying process (step S54).

In the cleaning process, first of all, the first cleaning solutionsupply process (step S51) is performed. In the first cleaning solutionsupply process (step S51), the developed wafer W is rotated and thecleaning solution is supplied to a central area of the rotated wafer W.FIG. 29A shows a status of the wafer W in the first cleaning solutionsupply process (step S51).

As depicted in FIG. 29A, the cleaning solution nozzle 6 a is positionedabove the central area of the wafer W, and while the wafer holder 44 isbeing rotated at a rotational speed of about 1000 rpm, the cleaningsolution such as pure water is discharged to the central area of thewafer W from the cleaning solution nozzle 6 a at a flow rate of, e.g.,about 500 ml/min for, e.g., about 5 seconds. Consequently, the cleaningsolution spreads from the central area of the wafer W to the peripheryare of the wafer W by a centrifugal force and a liquid film is formed onthe entire surface of the wafer W.

Then, the second cleaning solution supply process (step S52) isperformed. In the second cleaning solution supply process (step S52),while a cleaning solution supply position where the cleaning solution issupplied to the rotating wafer W is moving from the central area of thewafer W toward the periphery area of the wafer W, the cleaning solutionis supplied to the wafer W. FIG. 29B shows a status of the wafer W inthe second cleaning solution supply process (step S52).

As depicted in FIG. 29B, the wafer holder 44 is rotated at a rotationalspeed of about 1500 rpm or higher, for example, about 2000 rpm. Whilethe wafer holder 44 is being rotated and the cleaning solution is beingdischarged at a flow rate of, for example, about 250 ml/min, thecleaning solution nozzle 6 a moves from the central area of the wafer Wtoward a preset position at a speed of, for example, about 20 mm/sec. Inthis way, by moving the cleaning solution supply position from thecentral area of the wafer W to the periphery area of the wafer W, adried area 300 is formed at the central area of the wafer W. That is,since the cleaning solution which has been supplied to the central areaof the wafer W is moved, the liquid film starts to be dried from thecentral area of the wafer W and the dried area 300 is formed at thecentral area of the wafer W. Then, the dried area 300 spreads toward theperiphery area of the wafer W.

Subsequently, the supply stop process (step S53) is performed. In thesupply stop process (step S53), the supply of the cleaning solution isstopped. FIG. 29C shows a status of the wafer in the supply stop process(step S53).

As depicted in FIG. 29C, at a position away from the central area of thewafer W by a preset distance toward the periphery area of the wafer W,the supply of the cleaning solution is stopped. Herein, “presetdistance” is, in a range of, for example, from about 50 mm to about 95mm. That is because if the position (cleaning solution supply position)of the cleaning solution nozzle 6 a is too far away from the centralarea of the wafer W when the supply of the cleaning solution is stopped,a centrifugal force applied to the cleaning solution is great and aliquid flow is in disarray, so that foreign substances such as dissolvedby-products or particles may remain on the wafer W. On the contrary, ifthe position (cleaning solution supply position) of the cleaningsolution nozzle 6 a is too close to the central area of the wafer W whenthe supply of the cleaning solution is stopped, the dried area 300quickly reaches the periphery of the wafer W and the cleaning solutioncannot be sufficiently widely spread toward the periphery area of thewafer W.

A processing time in the present embodiment includes a time forperforming the first cleaning solution supply process and a time forperforming the second cleaning solution supply process.

Thereafter, the drying process (step S54) is performed. In the dryingprocess (step S54), the wafer W is rotated and dried. FIGS. 29D and 29Eshow statuses of the wafer in the drying process (step S54).

After the discharge of the cleaning solution from the cleaning solutionnozzle 6 a is stopped in the supply stop process (step S53), the wafer Wis rotated at a rotational speed (i.e., about 2000 rpm in thisembodiment). Consequently, as depicted in FIG. 29D, the dried area 300spreads toward the outside. If the dried area 300 spreads as describedabove, an interface between an outer circumference of the dried area 300and an inner circumference of the cleaning solution is pressed outwardsand raised upwards due to evaporation of the liquid and foreignsubstances in an interface between the wafer W and the liquid areupswept and separated from the interface, and, thus, it becomes easy tomove the foreign substances to the outside of the wafer W.

Further, after the dried area 300 spreads to the periphery area of thewafer W, the cleaning solution nozzle 6 a may be retreated from thewafer W and liquid on the wafer W may be removed by a centrifugal forcecaused by the rotation of the wafer W so as to dry the wafer W asdepicted in FIG. 29E. In the drying process (step S54), a rotationalspeed of the wafer may be in a range of from about 2000 rpm to about2500 rpm.

In the cleaning process, if the cleaning solution is supplied to thewafer W while the cleaning solution supply position where the cleaningsolution is supplied to the rotating wafer W is moved from the centralarea of the wafer W toward the periphery area of the wafer W, a supplyamount of the cleaning solution is likely to be decreased at the centralarea of the wafer W as compared to the periphery area of the wafer W.Therefore, in accordance with the present embodiment, by preparing thefirst data and determining a processing time of the cleaning processbased on the first data, the processing time t may be determined so asto be substantially the same as the convergence time t1 when the linewidth CD2 of the second resist pattern P2 converges. Thus,non-uniformity in the line widths CD2 of the second resist pattern P2may be decreased in a single wafer surface without increasing theprocessing time t.

In the present embodiment, there has been explained a case where a gasnozzle is not included in the developing unit (DEV) 28 explained withreference to FIGS. 3 and 4. However, it is also possible to include thegas nozzle 7 explained with reference to FIGS. 3 and 4 in order to forman initially dried area at the central area of the wafer W. Further, inthe second cleaning solution supply process (step S52) or in the supplystop process (step S53), a gas may be supplied to the central area ofthe wafer W through the gas nozzle 7, and, thus, the initially driedarea may be formed at the central area of the wafer W.

Furthermore, in the same manner as the first modification example of thefirst embodiment, also in the present embodiment, the processing time tmay be determined based on a relationship between the processing time tand each of line widths CD2-1 and CD2-2 of the second resist pattern P2on the central area of the wafer W and the periphery area of the waferW.

Moreover, in the same manner as the second modification example of thefirst embodiment, also in the present embodiment, the first processingcondition may include other conditions such as a temperature T, a flowrate F, or a pH of the cleaning solution than the processing time t. Inthis case, the first developing process (step S115) shown in FIG. 19 maybe performed instead of the first developing process (step S15) shown inFIG. 28 and the second coating process (step 117) shown in FIG. 19 maybe performed instead of the second coating process (step S17) shown inFIG. 28.

In the same manner as the third modification example of the firstembodiment, also in the present embodiment, the first data may show arelationship between the processing time t, the second processingcondition under which the cleaning process is performed on the wafer Win the first process and the line width CD2 of the second resist patternP2. The second processing condition may include, for example, thetemperature T, the flow rate F, and the pH of the cleaning solution. Inthis case, the first developing process (step S135) shown in FIG. 23 maybe performed instead of the first developing process (step S15) shown inFIG. 28 and the second coating process (step 137) shown in FIG. 23 maybe performed instead of the second coating process (step S17) shown inFIG. 28.

In the same manner as the fourth modification example of the firstembodiment, also in the present embodiment, an acid processing solutionprocess in which the wafer W is processed by an acid processing solutionmay be performed after the first process before the second process. Inthis case, the first developing process (step S155) shown in FIG. 27 maybe performed instead of the first developing process (step S15) shown inFIG. 28 and the acid processing solution process (step 157) shown inFIG. 27 may be performed instead of the second coating process (stepS17) shown in FIG. 28. Further, as an acid processing solution, it maybe possible to use at least one of acids mentioned in the firstembodiment as it is or at least one of acids diluted with water or thelike.

Modification Example of Second Embodiment

Hereinafter, referring to FIGS. 30A to 31B, there will be explained asubstrate processing method in accordance with a modification example ofthe second embodiment.

The substrate processing method in accordance with the presentmodification example is different from the substrate processing methodof the second embodiment in that a cleaning solution supply positionwhere the cleaning solution is supplied to the wafer W is not moved in acleaning process.

Also in the present modification example, the substrate processingsystem, the developing unit, and the line width measurement apparatusexplained in the first embodiment may be used in the same manner as thesecond embodiment.

However, in the same manner as the second embodiment, instead of thecleaning solution nozzle 6 having the slit-shaped discharge opening 62explained with reference to FIGS. 5A and 5B, the cylindrical cleaningsolution nozzle 6 a may be used. FIGS. 30A to 30C show the state thatthe cleaning solution is supplied to the wafer W through the cylindricalcleaning solution nozzle 6 a.

Further, in the same manner as the second embodiment, also in thepresent modification example, the developing unit explained withreference to FIGS. 3 and 4 may not include the gas nozzle.

FIGS. 30A to 30C are perspective views showing a status of a wafer ineach process of a cleaning process in the present modification example.

The substrate processing method in accordance with the presentmodification example is the same as the substrate processing method inaccordance with the first embodiment except the cleaning process (stepS16). Therefore, explanation of other processes (step S11 to step S15and step S17 to step S20) than the cleaning process will be omitted.

The cleaning process of the substrate processing method in accordancewith the present modification example is different from the cleaningprocess of the substrate processing method in accordance with the secondembodiment in that the second cleaning solution supply process (stepS52) is omitted. That is, the cleaning process of the substrateprocessing method in accordance with the present modification exampleincludes the first cleaning solution supply process (step S51), thesupply stop process (step S53), and the drying process (step S54) of thesecond embodiment.

In the same manner as the second embodiment, the first cleaning solutionsupply process (step S51) is performed. FIG. 30A shows a status of thewafer in the first cleaning solution supply process (step S51).

Then, the supply stop process (step S53) is performed. In the supplystop process (step S53), when the cleaning solution nozzle 6 a ispositioned above the central area of the wafer W, the supply of thecleaning solution is stopped. FIG. 30B shows a status of the wafer W inthe supply stop process (step S53).

As depicted in FIG. 30B, while the cleaning solution nozzle 6 a ispositioned above the central area of the wafer W, the supply of thecleaning solution from the cleaning solution nozzle 6 a is stopped.Further, by stopping the supply of the cleaning solution, the dried area300 is formed at the central area of the wafer W.

Subsequently, the drying process (step S300) is performed. In the dryingprocess (step S54), the wafer W is rotated and dried. FIG. 30C shows astatus of the wafer in the drying process (step S54).

A processing time in the present modification example may include a timefor performing the first cleaning solution supply process.

In the same manner as the first embodiment, also in the modificationexample, by preparing first data in advance, an accurate convergencetime t1 can be obtained. Therefore, the processing time t is determinedto become substantially the same as the convergence time t1, so thatnon-uniformity in the line widths CD2 of the second resist pattern P2 ina surface of a single wafer can be decreased without increasing theprocessing time t.

Hereinafter, by using a comparative example 2 in which the first datahas not been prepared in advance, there will be explained a comparisonresult of distribution of the line widths CD2 of the second resistpattern P2 in a wafer surface.

FIGS. 31A and 31B show distribution of space widths of a second resistpattern in a wafer surface obtained by performing the substrateprocessing methods in accordance with the present modification exampleand the comparative example 2, respectively. Further, FIGS. 31A and 31Bshow the distribution of the space widths represented by a gray scaleusing substantially the same upper and lower limit values.

In the comparative example 2, as depicted in FIG. 31B, substantially thesame value is not shown over the entire surface of the wafer W, and,thus, it is deemed that a cleaning process is not performedsufficiently. Meanwhile, in the present modification example, asdepicted in FIG. 31A, substantially the same value is shown over theentire surface of the wafer W, and, thus, it is deemed that a cleaningprocess is performed sufficiently.

Further, non-uniformity CD3σ in the space width SP2′ (line width CD2) ofthe present modification example is smaller than that of the comparativeexample 2. Therefore, in accordance with the present modificationexample, non-uniformity in the space width SP2′ (line width CD2) in awafer surface can be decreased.

In the cleaning process, if the cleaning solution is supplied to thecentral area of the rotating wafer W, a supply amount of the cleaningsolution may be different between the central area of the wafer W andthe periphery area of the wafer W. Therefore, in accordance with thepresent modification example, by preparing the first data anddetermining a processing time of the cleaning process based on the firstdata, the processing time t may be determined so as to be substantiallythe same as the convergence time t1 when the line width CD2 of thesecond resist pattern P2 converges. Thus, non-uniformity in the linewidths CD2 of the second resist pattern P2 may be decreased in a singlewafer surface without increasing the processing time t.

In the same manner as the first modification example of the firstembodiment, also in the present modification example, the processingtime t may be determined based on a relationship between the processingtime t and each of the line widths CD2-1 and CD2-2 of the second resistpattern P2 on the central area of the wafer W and the periphery area ofthe wafer W.

Further, in the same manner as the second modification example of thefirst embodiment, also in the present modification example, the firstprocessing condition may include other conditions such as a temperatureT, a flow rate F, or a pH of the cleaning solution than the processingtime t.

Furthermore, in the same manner as the third modification example of thefirst embodiment, also in the present modification example, the firstdata may show a relationship among the processing time t, the secondprocessing condition under which the cleaning process is performed onthe wafer W in the first process and the line width CD2 of the secondresist pattern P2. Moreover, the second processing condition mayinclude, for example, the temperature T, flow rate F, and pH of thecleaning solution.

Moreover, in the same manner as the fourth modification example of thefirst embodiment, also in the present modification example, an acidprocessing solution process in which a wafer W is processed by an acidprocessing solution may be performed after the first process before thesecond process. As the acid cleaning solution, it may be possible to useat least one of acids mentioned in the first embodiment as it is or atleast one of acids diluted with water or the like.

The embodiments of the present invention have been described above, butthe present invention is not limited to the above-described embodimentsand can be changed or modified in various ways within a scope of thesubject matter of the present invention recited in the following claims.

From the first embodiment to the modification example of the secondembodiment, there has been explained a case where a gas supply positionis moved from a central area of a wafer toward a periphery area of thewafer while a cleaning solution supply position is moved from thecentral area of the wafer to the periphery area of the wafer or a casewhere the cleaning solution supply position is not moved from thecentral area of the wafer. In other various cleaning processes, firstdata may be prepared and a processing time of the cleaning process maybe determined based on the first data.

Further, the present disclosure may be applied to an apparatus in whicha process is performed on a semiconductor substrate, a glass substrate,or other various substrates.

1. A substrate processing method for processing a substrate, the methodcomprising: a first process of forming a first resist pattern byexposing the substrate having thereon a first resist film to lights,developing the exposed substrate and cleaning the developed substrate;and a second process of forming a second resist pattern by forming asecond on the substrate having thereon the first resist pattern,exposing the substrate having thereon the second resist film to lights,and developing the exposed substrate, wherein, a first processingcondition is determined based on first data showing a relationshipbetween a first processing condition under which a cleaning process isperformed on the substrate in the first process and a line width of thesecond resist pattern, and the first process is performed on thesubstrate under the determined first processing condition.
 2. Thesubstrate processing method of claim 1, wherein the first processingcondition includes a processing time for performing the cleaning processon the substrate.
 3. The substrate processing method of claim 2, whereinthe first data include a convergence time when line widths of the secondresist pattern converge to a constant value, and the processing time isdetermined so as to be substantially the same as the convergence timebased on the first data.
 4. The substrate processing method of claim 1,wherein the first processing condition includes a temperature of acleaning solution for cleaning the substrate.
 5. The substrateprocessing method of claim 1, wherein the first processing conditionincludes a flow rate of a cleaning solution for cleaning the substrate.6. The substrate processing method of claim 1, wherein the firstprocessing condition includes a pH of a cleaning solution for cleaningthe substrate.
 7. The substrate processing method of claim 2, furthercomprising: a data preparation process of preparing the first data byperforming the first process on each substrate of a substrate setincluding multiple substrates while varying the first processingcondition, performing the second process on each substrate on which thefirst process has been performed, and measuring the line width of thesecond resist pattern formed on each substrate.
 8. The substrateprocessing method of claim 2, wherein the first data show a relationshipbetween the first processing condition and the line width of the secondresist pattern formed on a central area of the substrate, and the firstprocessing condition is determined in order to allow a line width of thesecond resist pattern formed on the central area of the substrate to besubstantially the same as a line width of the second resist formed on aperipheral area of the substrate based on the first data and second datashowing a relationship between the first processing condition and theline width of the second resist pattern formed on the peripheral area ofthe substrate.
 9. The substrate processing method of claim 8, furthercomprising: a data preparation process of preparing the first data byperforming the first process on each substrate of a substrate setincluding multiple substrates while varying the first processingcondition, performing the second process on each substrate on which thefirst process has been performed, and measuring the line width of thesecond resist pattern formed on the central area of each substrate, andof preparing the second data by measuring the line width of the secondresist pattern formed on the peripheral area of each substrate.
 10. Thesubstrate processing method of claim 2, wherein the first data show arelationship between the processing time, second processing conditionunder which the cleaning process is performed on the substrate in thefirst process, and the line width of the second resist pattern, theprocessing time and the second processing condition are determined basedon the first data, and the first process is performed on a singlesubstrate under the determined second condition for the determinedprocessing time.
 11. The substrate processing method of claim 10,wherein the second processing condition includes a temperature of acleaning solution for cleaning the substrate.
 12. The substrateprocessing method of claim 10, wherein the second processing conditionincludes a flow rate of a cleaning solution for cleaning the substrate.13. The substrate processing method of claim 10, wherein the secondprocessing condition includes a pH of a cleaning solution for cleaningthe substrate.
 14. The substrate processing method of claim 10, furthercomprising: a data preparation process of preparing the first data byperforming the first process on each substrate of a substrate setincluding multiple substrates while varying the processing time or thesecond processing condition, performing the second process on eachsubstrate on which the first process has been performed, and measuringthe line width of the second resist pattern formed on each substrate.15. The substrate processing method of claim 10, wherein the first datashow a relationship between the processing time, the second processingcondition, and the line width of the second resist pattern formed on acentral area of the substrate, and the processing time and the secondprocessing condition are determined in order to allow a line width ofthe second resist pattern formed on the central area of the substrate tobe substantially the same as a line width of the second resist formed ona peripheral area of the substrate based on the first data and seconddata showing a relationship between the processing time, the secondprocessing condition, and the line width of the second resist patternformed on the peripheral area of the substrate.
 16. The substrateprocessing method of claim 15, further comprising: a data preparationprocess of preparing the first data by performing the first process oneach substrate of a substrate set including multiple substrates whilevarying the processing time or the second processing condition,performing the second process on each substrate on which the firstprocess has been performed, and measuring the line width of the secondresist pattern formed on the central area of each substrate, and ofpreparing the second data by measuring the line width of the secondresist pattern formed on the peripheral area of each substrate.
 17. Thesubstrate processing method of claim 2, wherein the first processincludes: a cleaning solution supply process of supplying a cleaningsolution to the substrate while the developed substrate is being rotatedand a cleaning solution supply position where the cleaning solution issupplied to the rotating substrate is moved from a central area of thesubstrate toward a peripheral area of the substrate; and a gas supplyprocess of supplying a gas toward the periphery area of the substrate ata downstream position of the cleaning solution supply position in arotation direction of the substrate, further wherein the processing timeincludes a time for performing the cleaning solution supply process. 18.The substrate processing method of claim 2, wherein the first processincludes: while the developed substrate is being rotated, a firstcleaning solution supply process of supplying a cleaning solution to acentral area of the rotating substrate, further wherein the processingtime includes a time for performing the first cleaning solution supplyprocess.
 19. The substrate processing method of claim 18, wherein thefirst process further includes: after the first cleaning solution supplyprocess, a second cleaning solution supply process of supplying thecleaning solution to the substrate while the cleaning solution supplyposition is moved from the central area of the substrate toward theperipheral area of the substrate, further wherein the processing timeincludes a time for performing the second cleaning solution supplyprocess.
 20. The substrate processing method of claim 1, furthercomprising: after the first process and before the second process, anacid processing solution process of processing the substrate by an acidprocessing solution.